diff --git a/backend/config/services.yaml b/backend/config/services.yaml
index 3c0ee2c..0455a2d 100644
--- a/backend/config/services.yaml
+++ b/backend/config/services.yaml
@@ -165,6 +165,10 @@ services:
     App\Administration\Application\Port\TeacherAssignmentChecker:
         alias: App\Administration\Infrastructure\Service\RepositoryTeacherAssignmentChecker
 
+    # Teacher Replacement Repository (Story 2.9 - Remplaçants temporaires)
+    App\Scolarite\Domain\Repository\TeacherReplacementRepository:
+        alias: App\Scolarite\Infrastructure\Persistence\Doctrine\DoctrineTeacherReplacementRepository
+
     # Student Guardian Repository (Story 2.7 - Liaison parents-enfants)
     App\Administration\Infrastructure\Persistence\Cache\CacheStudentGuardianRepository:
         arguments:
diff --git a/backend/migrations/Version20260215100000.php b/backend/migrations/Version20260215100000.php
new file mode 100644
index 0000000..ab0a613
--- /dev/null
+++ b/backend/migrations/Version20260215100000.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Creates the teacher_replacements and replacement_classes tables for Story 2.9.
+ *
+ * Models temporary teacher replacement: an admin designates a replacement teacher
+ * with start/end dates for specific class/subject pairs.
+ */
+final class Version20260215100000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Create teacher_replacements and replacement_classes tables (Story 2.9)';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql(<<<'SQL'
+            CREATE TABLE IF NOT EXISTS teacher_replacements (
+                id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+                tenant_id UUID NOT NULL,
+                replaced_teacher_id UUID NOT NULL,
+                replacement_teacher_id UUID NOT NULL,
+                start_date DATE NOT NULL,
+                end_date DATE NOT NULL,
+                status VARCHAR(20) NOT NULL DEFAULT 'active',
+                reason TEXT,
+                created_by UUID NOT NULL,
+                created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+                ended_at TIMESTAMPTZ,
+                updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+                CONSTRAINT valid_dates CHECK (end_date >= start_date),
+                CONSTRAINT different_teachers CHECK (replaced_teacher_id != replacement_teacher_id)
+            )
+        SQL);
+
+        $this->addSql(<<<'SQL'
+            CREATE TABLE IF NOT EXISTS replacement_classes (
+                replacement_id UUID NOT NULL REFERENCES teacher_replacements(id) ON DELETE CASCADE,
+                class_id UUID NOT NULL,
+                subject_id UUID NOT NULL,
+                PRIMARY KEY (replacement_id, class_id, subject_id)
+            )
+        SQL);
+
+        $this->addSql('CREATE INDEX idx_replacements_tenant ON teacher_replacements(tenant_id)');
+        $this->addSql('CREATE INDEX idx_replacements_dates ON teacher_replacements(start_date, end_date)');
+        $this->addSql('CREATE INDEX idx_replacements_status ON teacher_replacements(status)');
+        $this->addSql('CREATE INDEX idx_replacements_replaced_teacher ON teacher_replacements(replaced_teacher_id)');
+        $this->addSql('CREATE INDEX idx_replacements_replacement_teacher ON teacher_replacements(replacement_teacher_id)');
+        $this->addSql('CREATE INDEX idx_replacements_tenant_status ON teacher_replacements(tenant_id, status)');
+        $this->addSql('CREATE INDEX idx_replacements_status_end_date ON teacher_replacements(status, end_date)');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('DROP TABLE IF EXISTS replacement_classes');
+        $this->addSql('DROP TABLE IF EXISTS teacher_replacements');
+    }
+}
diff --git a/backend/src/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementCommand.php b/backend/src/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementCommand.php
new file mode 100644
index 0000000..5124025
--- /dev/null
+++ b/backend/src/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementCommand.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Command\DesignateReplacement;
+
+final readonly class DesignateReplacementCommand
+{
+    /**
+     * @param array<array{classId: string, subjectId: string}> $classes
+     */
+    public function __construct(
+        public string $tenantId,
+        public string $replacedTeacherId,
+        public string $replacementTeacherId,
+        public string $startDate,
+        public string $endDate,
+        public array $classes,
+        public ?string $reason,
+        public string $createdBy,
+    ) {
+    }
+}
diff --git a/backend/src/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementHandler.php b/backend/src/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementHandler.php
new file mode 100644
index 0000000..9313158
--- /dev/null
+++ b/backend/src/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementHandler.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Command\DesignateReplacement;
+
+use App\Administration\Domain\Exception\TenantMismatchException;
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\Role;
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Domain\Repository\UserRepository;
+use App\Scolarite\Domain\Exception\UtilisateurNonEnseignantException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use Symfony\Component\Messenger\Attribute\AsMessageHandler;
+
+#[AsMessageHandler(bus: 'command.bus')]
+final readonly class DesignateReplacementHandler
+{
+    public function __construct(
+        private TeacherReplacementRepository $replacementRepository,
+        private UserRepository $userRepository,
+        private Clock $clock,
+    ) {
+    }
+
+    public function __invoke(DesignateReplacementCommand $command): TeacherReplacement
+    {
+        $tenantId = TenantId::fromString($command->tenantId);
+        $replacedTeacherId = UserId::fromString($command->replacedTeacherId);
+        $replacementTeacherId = UserId::fromString($command->replacementTeacherId);
+
+        // Valider l'existence, le tenant et le rôle des enseignants
+        $replacedTeacher = $this->userRepository->get($replacedTeacherId);
+        if (!$replacedTeacher->tenantId->equals($tenantId)) {
+            throw TenantMismatchException::pourUtilisateur($replacedTeacherId, $tenantId);
+        }
+        if (!$replacedTeacher->aLeRole(Role::PROF)) {
+            throw UtilisateurNonEnseignantException::pourUtilisateur($replacedTeacherId);
+        }
+
+        $replacementTeacher = $this->userRepository->get($replacementTeacherId);
+        if (!$replacementTeacher->tenantId->equals($tenantId)) {
+            throw TenantMismatchException::pourUtilisateur($replacementTeacherId, $tenantId);
+        }
+        if (!$replacementTeacher->aLeRole(Role::PROF)) {
+            throw UtilisateurNonEnseignantException::pourUtilisateur($replacementTeacherId);
+        }
+
+        $classes = array_map(
+            static fn (array $pair) => new ClassSubjectPair(
+                ClassId::fromString($pair['classId']),
+                SubjectId::fromString($pair['subjectId']),
+            ),
+            $command->classes,
+        );
+
+        $replacement = TeacherReplacement::designer(
+            tenantId: $tenantId,
+            replacedTeacherId: $replacedTeacherId,
+            replacementTeacherId: $replacementTeacherId,
+            startDate: new DateTimeImmutable($command->startDate),
+            endDate: new DateTimeImmutable($command->endDate),
+            classes: $classes,
+            reason: $command->reason,
+            createdBy: UserId::fromString($command->createdBy),
+            now: $this->clock->now(),
+        );
+
+        $this->replacementRepository->save($replacement);
+
+        return $replacement;
+    }
+}
diff --git a/backend/src/Scolarite/Application/Command/EndReplacement/EndReplacementCommand.php b/backend/src/Scolarite/Application/Command/EndReplacement/EndReplacementCommand.php
new file mode 100644
index 0000000..1573db2
--- /dev/null
+++ b/backend/src/Scolarite/Application/Command/EndReplacement/EndReplacementCommand.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Command\EndReplacement;
+
+final readonly class EndReplacementCommand
+{
+    public function __construct(
+        public string $replacementId,
+        public string $tenantId,
+    ) {
+    }
+}
diff --git a/backend/src/Scolarite/Application/Command/EndReplacement/EndReplacementHandler.php b/backend/src/Scolarite/Application/Command/EndReplacement/EndReplacementHandler.php
new file mode 100644
index 0000000..75d4d63
--- /dev/null
+++ b/backend/src/Scolarite/Application/Command/EndReplacement/EndReplacementHandler.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Command\EndReplacement;
+
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use Symfony\Component\Messenger\Attribute\AsMessageHandler;
+
+#[AsMessageHandler(bus: 'command.bus')]
+final readonly class EndReplacementHandler
+{
+    public function __construct(
+        private TeacherReplacementRepository $replacementRepository,
+        private Clock $clock,
+    ) {
+    }
+
+    public function __invoke(EndReplacementCommand $command): void
+    {
+        $replacement = $this->replacementRepository->get(
+            TeacherReplacementId::fromString($command->replacementId),
+            TenantId::fromString($command->tenantId),
+        );
+
+        $replacement->terminer($this->clock->now());
+        $this->replacementRepository->save($replacement);
+    }
+}
diff --git a/backend/src/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsHandler.php b/backend/src/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsHandler.php
new file mode 100644
index 0000000..ad86d0d
--- /dev/null
+++ b/backend/src/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsHandler.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetActiveReplacements;
+
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use Symfony\Component\Messenger\Attribute\AsMessageHandler;
+
+#[AsMessageHandler(bus: 'query.bus')]
+final readonly class GetActiveReplacementsHandler
+{
+    public function __construct(
+        private TeacherReplacementRepository $replacementRepository,
+        private Clock $clock,
+    ) {
+    }
+
+    /** @return array<ReplacementDto> */
+    public function __invoke(GetActiveReplacementsQuery $query): array
+    {
+        $replacements = $this->replacementRepository->findActiveByTenant(
+            TenantId::fromString($query->tenantId),
+            $this->clock->now(),
+        );
+
+        return array_map(
+            static fn ($r) => ReplacementDto::fromDomain($r),
+            $replacements,
+        );
+    }
+}
diff --git a/backend/src/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsQuery.php b/backend/src/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsQuery.php
new file mode 100644
index 0000000..8b5c501
--- /dev/null
+++ b/backend/src/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsQuery.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetActiveReplacements;
+
+final readonly class GetActiveReplacementsQuery
+{
+    public function __construct(
+        public string $tenantId,
+    ) {
+    }
+}
diff --git a/backend/src/Scolarite/Application/Query/GetActiveReplacements/ReplacementDto.php b/backend/src/Scolarite/Application/Query/GetActiveReplacements/ReplacementDto.php
new file mode 100644
index 0000000..22bfd5f
--- /dev/null
+++ b/backend/src/Scolarite/Application/Query/GetActiveReplacements/ReplacementDto.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetActiveReplacements;
+
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use DateTimeImmutable;
+
+final readonly class ReplacementDto
+{
+    /** @param array<array{classId: string, subjectId: string}> $classes */
+    public function __construct(
+        public string $id,
+        public string $replacedTeacherId,
+        public string $replacementTeacherId,
+        public DateTimeImmutable $startDate,
+        public DateTimeImmutable $endDate,
+        public string $status,
+        public array $classes,
+        public ?string $reason,
+    ) {
+    }
+
+    public static function fromDomain(TeacherReplacement $replacement): self
+    {
+        return new self(
+            id: (string) $replacement->id,
+            replacedTeacherId: (string) $replacement->replacedTeacherId,
+            replacementTeacherId: (string) $replacement->replacementTeacherId,
+            startDate: $replacement->startDate,
+            endDate: $replacement->endDate,
+            status: $replacement->status->value,
+            classes: array_map(
+                static fn ($pair) => [
+                    'classId' => (string) $pair->classId,
+                    'subjectId' => (string) $pair->subjectId,
+                ],
+                $replacement->classes,
+            ),
+            reason: $replacement->reason,
+        );
+    }
+}
diff --git a/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherHandler.php b/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherHandler.php
new file mode 100644
index 0000000..29eed0f
--- /dev/null
+++ b/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherHandler.php
@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetReplacedClassesForTeacher;
+
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Domain\Repository\ClassRepository;
+use App\Administration\Domain\Repository\SubjectRepository;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use Symfony\Component\Messenger\Attribute\AsMessageHandler;
+
+#[AsMessageHandler(bus: 'query.bus')]
+final readonly class GetReplacedClassesForTeacherHandler
+{
+    public function __construct(
+        private TeacherReplacementRepository $replacementRepository,
+        private ClassRepository $classRepository,
+        private SubjectRepository $subjectRepository,
+        private Clock $clock,
+    ) {
+    }
+
+    /** @return array<ReplacedClassDto> */
+    public function __invoke(GetReplacedClassesForTeacherQuery $query): array
+    {
+        $tenantId = TenantId::fromString($query->tenantId);
+
+        $replacements = $this->replacementRepository->findActiveByReplacementTeacher(
+            UserId::fromString($query->replacementTeacherId),
+            $tenantId,
+            $this->clock->now(),
+        );
+
+        if ($replacements === []) {
+            return [];
+        }
+
+        $classNames = [];
+        foreach ($this->classRepository->findAllActiveByTenant($tenantId) as $class) {
+            $classNames[(string) $class->id] = (string) $class->name;
+        }
+
+        $subjectNames = [];
+        foreach ($this->subjectRepository->findAllActiveByTenant($tenantId) as $subject) {
+            $subjectNames[(string) $subject->id] = (string) $subject->name;
+        }
+
+        $result = [];
+
+        foreach ($replacements as $replacement) {
+            foreach ($replacement->classes as $pair) {
+                $classId = (string) $pair->classId;
+                $subjectId = (string) $pair->subjectId;
+
+                $result[] = new ReplacedClassDto(
+                    replacementId: (string) $replacement->id,
+                    replacedTeacherId: (string) $replacement->replacedTeacherId,
+                    classId: $classId,
+                    subjectId: $subjectId,
+                    className: $classNames[$classId] ?? $classId,
+                    subjectName: $subjectNames[$subjectId] ?? $subjectId,
+                    startDate: $replacement->startDate,
+                    endDate: $replacement->endDate,
+                );
+            }
+        }
+
+        return $result;
+    }
+}
diff --git a/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherQuery.php b/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherQuery.php
new file mode 100644
index 0000000..8a33180
--- /dev/null
+++ b/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherQuery.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetReplacedClassesForTeacher;
+
+final readonly class GetReplacedClassesForTeacherQuery
+{
+    public function __construct(
+        public string $replacementTeacherId,
+        public string $tenantId,
+    ) {
+    }
+}
diff --git a/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/ReplacedClassDto.php b/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/ReplacedClassDto.php
new file mode 100644
index 0000000..9bfb822
--- /dev/null
+++ b/backend/src/Scolarite/Application/Query/GetReplacedClassesForTeacher/ReplacedClassDto.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetReplacedClassesForTeacher;
+
+use DateTimeImmutable;
+
+final readonly class ReplacedClassDto
+{
+    public function __construct(
+        public string $replacementId,
+        public string $replacedTeacherId,
+        public string $classId,
+        public string $subjectId,
+        public string $className,
+        public string $subjectName,
+        public DateTimeImmutable $startDate,
+        public DateTimeImmutable $endDate,
+    ) {
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Event/RemplacementDesigne.php b/backend/src/Scolarite/Domain/Event/RemplacementDesigne.php
new file mode 100644
index 0000000..18a91be
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Event/RemplacementDesigne.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Event;
+
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Shared\Domain\DomainEvent;
+use DateTimeImmutable;
+use Override;
+use Ramsey\Uuid\UuidInterface;
+
+final readonly class RemplacementDesigne implements DomainEvent
+{
+    public function __construct(
+        public TeacherReplacementId $replacementId,
+        public UserId $replacedTeacherId,
+        public UserId $replacementTeacherId,
+        public DateTimeImmutable $startDate,
+        public DateTimeImmutable $endDate,
+        private DateTimeImmutable $occurredOn,
+    ) {
+    }
+
+    #[Override]
+    public function occurredOn(): DateTimeImmutable
+    {
+        return $this->occurredOn;
+    }
+
+    #[Override]
+    public function aggregateId(): UuidInterface
+    {
+        return $this->replacementId->value;
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Event/RemplacementTermine.php b/backend/src/Scolarite/Domain/Event/RemplacementTermine.php
new file mode 100644
index 0000000..b95a745
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Event/RemplacementTermine.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Event;
+
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Shared\Domain\DomainEvent;
+use DateTimeImmutable;
+use Override;
+use Ramsey\Uuid\UuidInterface;
+
+final readonly class RemplacementTermine implements DomainEvent
+{
+    public function __construct(
+        public TeacherReplacementId $replacementId,
+        public UserId $replacedTeacherId,
+        public UserId $replacementTeacherId,
+        public DateTimeImmutable $startDate,
+        public DateTimeImmutable $endDate,
+        private DateTimeImmutable $occurredOn,
+    ) {
+    }
+
+    #[Override]
+    public function occurredOn(): DateTimeImmutable
+    {
+        return $this->occurredOn;
+    }
+
+    #[Override]
+    public function aggregateId(): UuidInterface
+    {
+        return $this->replacementId->value;
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Exception/DatesRemplacementInvalidesException.php b/backend/src/Scolarite/Domain/Exception/DatesRemplacementInvalidesException.php
new file mode 100644
index 0000000..2c7756c
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Exception/DatesRemplacementInvalidesException.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Exception;
+
+use DateTimeImmutable;
+use DomainException;
+
+use function sprintf;
+
+final class DatesRemplacementInvalidesException extends DomainException
+{
+    public static function finAvantDebut(DateTimeImmutable $startDate, DateTimeImmutable $endDate): self
+    {
+        return new self(sprintf(
+            'La date de début (%s) doit être antérieure à la date de fin (%s).',
+            $startDate->format('Y-m-d'),
+            $endDate->format('Y-m-d'),
+        ));
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Exception/RemplacementDejaTermineException.php b/backend/src/Scolarite/Domain/Exception/RemplacementDejaTermineException.php
new file mode 100644
index 0000000..5064f24
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Exception/RemplacementDejaTermineException.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Exception;
+
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use DomainException;
+
+use function sprintf;
+
+final class RemplacementDejaTermineException extends DomainException
+{
+    public static function withId(TeacherReplacementId $id): self
+    {
+        return new self(sprintf(
+            'Le remplacement "%s" est déjà terminé.',
+            $id,
+        ));
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Exception/RemplacementNotFoundException.php b/backend/src/Scolarite/Domain/Exception/RemplacementNotFoundException.php
new file mode 100644
index 0000000..3599801
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Exception/RemplacementNotFoundException.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Exception;
+
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use DomainException;
+
+use function sprintf;
+
+final class RemplacementNotFoundException extends DomainException
+{
+    public static function withId(TeacherReplacementId $id): self
+    {
+        return new self(sprintf(
+            'Le remplacement avec l\'ID "%s" n\'a pas été trouvé.',
+            $id,
+        ));
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Exception/RemplacementSameTeacherException.php b/backend/src/Scolarite/Domain/Exception/RemplacementSameTeacherException.php
new file mode 100644
index 0000000..489788b
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Exception/RemplacementSameTeacherException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Exception;
+
+use DomainException;
+
+final class RemplacementSameTeacherException extends DomainException
+{
+    public static function create(): self
+    {
+        return new self('L\'enseignant remplacé et le remplaçant ne peuvent pas être la même personne.');
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Exception/UtilisateurNonEnseignantException.php b/backend/src/Scolarite/Domain/Exception/UtilisateurNonEnseignantException.php
new file mode 100644
index 0000000..228974e
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Exception/UtilisateurNonEnseignantException.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Exception;
+
+use App\Administration\Domain\Model\User\UserId;
+use DomainException;
+
+use function sprintf;
+
+final class UtilisateurNonEnseignantException extends DomainException
+{
+    public static function pourUtilisateur(UserId $userId): self
+    {
+        return new self(sprintf(
+            'L\'utilisateur « %s » n\'a pas le rôle enseignant.',
+            $userId,
+        ));
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Model/TeacherReplacement/ClassSubjectPair.php b/backend/src/Scolarite/Domain/Model/TeacherReplacement/ClassSubjectPair.php
new file mode 100644
index 0000000..05289c6
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Model/TeacherReplacement/ClassSubjectPair.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Model\TeacherReplacement;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+
+final readonly class ClassSubjectPair
+{
+    public function __construct(
+        public ClassId $classId,
+        public SubjectId $subjectId,
+    ) {
+    }
+
+    public function equals(self $other): bool
+    {
+        return $this->classId->equals($other->classId)
+            && $this->subjectId->equals($other->subjectId);
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Model/TeacherReplacement/ReplacementStatus.php b/backend/src/Scolarite/Domain/Model/TeacherReplacement/ReplacementStatus.php
new file mode 100644
index 0000000..7168eee
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Model/TeacherReplacement/ReplacementStatus.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Model\TeacherReplacement;
+
+enum ReplacementStatus: string
+{
+    case ACTIVE = 'active';
+    case ENDED = 'ended';
+
+    public function estActive(): bool
+    {
+        return $this === self::ACTIVE;
+    }
+
+    public function label(): string
+    {
+        return match ($this) {
+            self::ACTIVE => 'Actif',
+            self::ENDED => 'Terminé',
+        };
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacement.php b/backend/src/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacement.php
new file mode 100644
index 0000000..cc05932
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacement.php
@@ -0,0 +1,185 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Model\TeacherReplacement;
+
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Event\RemplacementDesigne;
+use App\Scolarite\Domain\Event\RemplacementTermine;
+use App\Scolarite\Domain\Exception\DatesRemplacementInvalidesException;
+use App\Scolarite\Domain\Exception\RemplacementDejaTermineException;
+use App\Scolarite\Domain\Exception\RemplacementSameTeacherException;
+use App\Shared\Domain\AggregateRoot;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use InvalidArgumentException;
+
+/**
+ * Aggregate Root représentant le remplacement temporaire d'un enseignant.
+ *
+ * Un administrateur désigne un remplaçant pour un enseignant absent, avec des dates
+ * de début/fin et un périmètre de classes/matières. Le remplaçant peut saisir de
+ * nouvelles notes et lire les notes passées (lecture seule).
+ *
+ * @see FR9: Désigner remplaçant temporaire
+ */
+final class TeacherReplacement extends AggregateRoot
+{
+    public private(set) DateTimeImmutable $updatedAt;
+
+    /** @param array<ClassSubjectPair> $classes */
+    private function __construct(
+        public private(set) TeacherReplacementId $id,
+        public private(set) TenantId $tenantId,
+        public private(set) UserId $replacedTeacherId,
+        public private(set) UserId $replacementTeacherId,
+        public private(set) DateTimeImmutable $startDate,
+        public private(set) DateTimeImmutable $endDate,
+        public private(set) ReplacementStatus $status,
+        public private(set) array $classes,
+        public private(set) ?string $reason,
+        public private(set) UserId $createdBy,
+        public private(set) DateTimeImmutable $createdAt,
+        public private(set) ?DateTimeImmutable $endedAt,
+    ) {
+        $this->updatedAt = $createdAt;
+    }
+
+    /** @param array<ClassSubjectPair> $classes */
+    public static function designer(
+        TenantId $tenantId,
+        UserId $replacedTeacherId,
+        UserId $replacementTeacherId,
+        DateTimeImmutable $startDate,
+        DateTimeImmutable $endDate,
+        array $classes,
+        ?string $reason,
+        UserId $createdBy,
+        DateTimeImmutable $now,
+    ): self {
+        if ($replacedTeacherId->equals($replacementTeacherId)) {
+            throw RemplacementSameTeacherException::create();
+        }
+
+        if ($endDate < $startDate) {
+            throw DatesRemplacementInvalidesException::finAvantDebut($startDate, $endDate);
+        }
+
+        if ($classes === []) {
+            throw new InvalidArgumentException('Au moins une paire classe/matière est requise.');
+        }
+
+        $replacement = new self(
+            id: TeacherReplacementId::generate(),
+            tenantId: $tenantId,
+            replacedTeacherId: $replacedTeacherId,
+            replacementTeacherId: $replacementTeacherId,
+            startDate: $startDate,
+            endDate: $endDate,
+            status: ReplacementStatus::ACTIVE,
+            classes: $classes,
+            reason: $reason,
+            createdBy: $createdBy,
+            createdAt: $now,
+            endedAt: null,
+        );
+
+        $replacement->recordEvent(new RemplacementDesigne(
+            replacementId: $replacement->id,
+            replacedTeacherId: $replacedTeacherId,
+            replacementTeacherId: $replacementTeacherId,
+            startDate: $startDate,
+            endDate: $endDate,
+            occurredOn: $now,
+        ));
+
+        return $replacement;
+    }
+
+    public function isActive(DateTimeImmutable $now): bool
+    {
+        return $this->status === ReplacementStatus::ACTIVE
+            && $now >= $this->startDate
+            && $now <= $this->endDate;
+    }
+
+    public function isExpired(DateTimeImmutable $now): bool
+    {
+        return $this->status === ReplacementStatus::ACTIVE
+            && $now > $this->endDate;
+    }
+
+    public function terminer(DateTimeImmutable $at): void
+    {
+        if ($this->status === ReplacementStatus::ENDED) {
+            throw RemplacementDejaTermineException::withId($this->id);
+        }
+
+        $this->status = ReplacementStatus::ENDED;
+        $this->endedAt = $at;
+        $this->updatedAt = $at;
+
+        $this->recordEvent(new RemplacementTermine(
+            replacementId: $this->id,
+            replacedTeacherId: $this->replacedTeacherId,
+            replacementTeacherId: $this->replacementTeacherId,
+            startDate: $this->startDate,
+            endDate: $this->endDate,
+            occurredOn: $at,
+        ));
+    }
+
+    public function couvreClasseMatiere(ClassSubjectPair $pair): bool
+    {
+        foreach ($this->classes as $classSubjectPair) {
+            if ($classSubjectPair->equals($pair)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Reconstitue un TeacherReplacement depuis le stockage.
+     *
+     * @internal Pour usage Infrastructure uniquement
+     *
+     * @param array<ClassSubjectPair> $classes
+     */
+    public static function reconstitute(
+        TeacherReplacementId $id,
+        TenantId $tenantId,
+        UserId $replacedTeacherId,
+        UserId $replacementTeacherId,
+        DateTimeImmutable $startDate,
+        DateTimeImmutable $endDate,
+        ReplacementStatus $status,
+        array $classes,
+        ?string $reason,
+        UserId $createdBy,
+        DateTimeImmutable $createdAt,
+        ?DateTimeImmutable $endedAt,
+        DateTimeImmutable $updatedAt,
+    ): self {
+        $replacement = new self(
+            id: $id,
+            tenantId: $tenantId,
+            replacedTeacherId: $replacedTeacherId,
+            replacementTeacherId: $replacementTeacherId,
+            startDate: $startDate,
+            endDate: $endDate,
+            status: $status,
+            classes: $classes,
+            reason: $reason,
+            createdBy: $createdBy,
+            createdAt: $createdAt,
+            endedAt: $endedAt,
+        );
+
+        $replacement->updatedAt = $updatedAt;
+
+        return $replacement;
+    }
+}
diff --git a/backend/src/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacementId.php b/backend/src/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacementId.php
new file mode 100644
index 0000000..110634a
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacementId.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Model\TeacherReplacement;
+
+use App\Shared\Domain\EntityId;
+
+final readonly class TeacherReplacementId extends EntityId
+{
+}
diff --git a/backend/src/Scolarite/Domain/Repository/TeacherReplacementRepository.php b/backend/src/Scolarite/Domain/Repository/TeacherReplacementRepository.php
new file mode 100644
index 0000000..403a462
--- /dev/null
+++ b/backend/src/Scolarite/Domain/Repository/TeacherReplacementRepository.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Domain\Repository;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Exception\RemplacementNotFoundException;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+
+interface TeacherReplacementRepository
+{
+    public function save(TeacherReplacement $replacement): void;
+
+    /** @throws RemplacementNotFoundException */
+    public function get(TeacherReplacementId $id, TenantId $tenantId): TeacherReplacement;
+
+    public function findById(TeacherReplacementId $id, TenantId $tenantId): ?TeacherReplacement;
+
+    public function findActiveReplacement(
+        UserId $replacementTeacherId,
+        ClassId $classId,
+        SubjectId $subjectId,
+        DateTimeImmutable $at,
+        TenantId $tenantId,
+    ): ?TeacherReplacement;
+
+    /** @return array<TeacherReplacement> */
+    public function findActiveByTenant(TenantId $tenantId, DateTimeImmutable $at): array;
+
+    /** @return array<TeacherReplacement> */
+    public function findActiveByReplacementTeacher(
+        UserId $replacementTeacherId,
+        TenantId $tenantId,
+        DateTimeImmutable $at,
+    ): array;
+
+    /** @return array<TeacherReplacement> */
+    public function findExpired(DateTimeImmutable $at): array;
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Processor/CreateTeacherReplacementProcessor.php b/backend/src/Scolarite/Infrastructure/Api/Processor/CreateTeacherReplacementProcessor.php
new file mode 100644
index 0000000..56bfd2d
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Processor/CreateTeacherReplacementProcessor.php
@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Processor;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProcessorInterface;
+use App\Administration\Domain\Exception\TenantMismatchException;
+use App\Administration\Domain\Exception\UserNotFoundException;
+use App\Administration\Infrastructure\Security\SecurityUser;
+use App\Scolarite\Application\Command\DesignateReplacement\DesignateReplacementCommand;
+use App\Scolarite\Application\Command\DesignateReplacement\DesignateReplacementHandler;
+use App\Scolarite\Domain\Exception\DatesRemplacementInvalidesException;
+use App\Scolarite\Domain\Exception\RemplacementSameTeacherException;
+use App\Scolarite\Domain\Exception\UtilisateurNonEnseignantException;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Security\TeacherReplacementVoter;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use Override;
+use Ramsey\Uuid\Exception\InvalidUuidStringException;
+use Symfony\Bundle\SecurityBundle\Security;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+/**
+ * @implements ProcessorInterface<TeacherReplacementResource, TeacherReplacementResource>
+ */
+final readonly class CreateTeacherReplacementProcessor implements ProcessorInterface
+{
+    public function __construct(
+        private DesignateReplacementHandler $handler,
+        private TenantContext $tenantContext,
+        private MessageBusInterface $eventBus,
+        private AuthorizationCheckerInterface $authorizationChecker,
+        private Security $security,
+    ) {
+    }
+
+    /**
+     * @param TeacherReplacementResource $data
+     */
+    #[Override]
+    public function process(mixed $data, Operation $operation, array $uriVariables = [], array $context = []): TeacherReplacementResource
+    {
+        if (!$this->authorizationChecker->isGranted(TeacherReplacementVoter::CREATE)) {
+            throw new AccessDeniedHttpException('Vous n\'êtes pas autorisé à créer un remplacement.');
+        }
+
+        if (!$this->tenantContext->hasTenant()) {
+            throw new UnauthorizedHttpException('Bearer', 'Tenant non défini.');
+        }
+
+        $user = $this->security->getUser();
+
+        if (!$user instanceof SecurityUser) {
+            throw new UnauthorizedHttpException('Bearer', 'Authentification requise.');
+        }
+
+        try {
+            $command = new DesignateReplacementCommand(
+                tenantId: (string) $this->tenantContext->getCurrentTenantId(),
+                replacedTeacherId: $data->replacedTeacherId ?? '',
+                replacementTeacherId: $data->replacementTeacherId ?? '',
+                startDate: $data->startDate ?? '',
+                endDate: $data->endDate ?? '',
+                classes: $data->classes ?? [],
+                reason: $data->reason,
+                createdBy: $user->userId(),
+            );
+
+            $replacement = ($this->handler)($command);
+
+            foreach ($replacement->pullDomainEvents() as $event) {
+                $this->eventBus->dispatch($event);
+            }
+
+            return TeacherReplacementResource::fromDomain($replacement);
+        } catch (RemplacementSameTeacherException|DatesRemplacementInvalidesException|TenantMismatchException|UtilisateurNonEnseignantException $e) {
+            throw new BadRequestHttpException($e->getMessage());
+        } catch (UserNotFoundException $e) {
+            throw new NotFoundHttpException($e->getMessage());
+        } catch (InvalidUuidStringException $e) {
+            throw new BadRequestHttpException('UUID invalide : ' . $e->getMessage());
+        }
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Processor/EndTeacherReplacementProcessor.php b/backend/src/Scolarite/Infrastructure/Api/Processor/EndTeacherReplacementProcessor.php
new file mode 100644
index 0000000..c64aa1a
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Processor/EndTeacherReplacementProcessor.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Processor;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProcessorInterface;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementCommand;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementHandler;
+use App\Scolarite\Domain\Exception\RemplacementDejaTermineException;
+use App\Scolarite\Domain\Exception\RemplacementNotFoundException;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Security\TeacherReplacementVoter;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use Override;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+/**
+ * @implements ProcessorInterface<TeacherReplacementResource, null>
+ */
+final readonly class EndTeacherReplacementProcessor implements ProcessorInterface
+{
+    public function __construct(
+        private EndReplacementHandler $handler,
+        private TenantContext $tenantContext,
+        private AuthorizationCheckerInterface $authorizationChecker,
+    ) {
+    }
+
+    #[Override]
+    public function process(mixed $data, Operation $operation, array $uriVariables = [], array $context = []): null
+    {
+        if (!$this->authorizationChecker->isGranted(TeacherReplacementVoter::DELETE)) {
+            throw new AccessDeniedHttpException('Vous n\'êtes pas autorisé à terminer un remplacement.');
+        }
+
+        if (!$this->tenantContext->hasTenant()) {
+            throw new UnauthorizedHttpException('Bearer', 'Tenant non défini.');
+        }
+
+        /** @var string $id */
+        $id = $uriVariables['id'];
+
+        try {
+            ($this->handler)(new EndReplacementCommand(
+                replacementId: $id,
+                tenantId: (string) $this->tenantContext->getCurrentTenantId(),
+            ));
+        } catch (RemplacementNotFoundException $e) {
+            throw new NotFoundHttpException($e->getMessage());
+        } catch (RemplacementDejaTermineException $e) {
+            throw new BadRequestHttpException($e->getMessage());
+        }
+
+        return null;
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Provider/ReplacedClassesProvider.php b/backend/src/Scolarite/Infrastructure/Api/Provider/ReplacedClassesProvider.php
new file mode 100644
index 0000000..80e5fc1
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Provider/ReplacedClassesProvider.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Provider;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+use App\Administration\Infrastructure\Security\SecurityUser;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\GetReplacedClassesForTeacherHandler;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\GetReplacedClassesForTeacherQuery;
+use App\Scolarite\Infrastructure\Api\Resource\ReplacedClassResource;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use Override;
+use Symfony\Bundle\SecurityBundle\Security;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+
+/**
+ * Fournit les classes du remplaçant connecté (GET /api/me/replaced-classes).
+ *
+ * @implements ProviderInterface<ReplacedClassResource>
+ */
+final readonly class ReplacedClassesProvider implements ProviderInterface
+{
+    public function __construct(
+        private GetReplacedClassesForTeacherHandler $handler,
+        private TenantContext $tenantContext,
+        private Security $security,
+    ) {
+    }
+
+    /** @return array<ReplacedClassResource> */
+    #[Override]
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): array
+    {
+        $user = $this->security->getUser();
+
+        if (!$user instanceof SecurityUser) {
+            throw new UnauthorizedHttpException('Bearer', 'Authentification requise.');
+        }
+
+        if (!$this->tenantContext->hasTenant()) {
+            throw new UnauthorizedHttpException('Bearer', 'Tenant non défini.');
+        }
+
+        $query = new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: $user->userId(),
+            tenantId: (string) $this->tenantContext->getCurrentTenantId(),
+        );
+
+        return array_map(
+            ReplacedClassResource::fromDto(...),
+            ($this->handler)($query),
+        );
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Provider/TeacherReplacementItemProvider.php b/backend/src/Scolarite/Infrastructure/Api/Provider/TeacherReplacementItemProvider.php
new file mode 100644
index 0000000..5ee81cf
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Provider/TeacherReplacementItemProvider.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Provider;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Security\TeacherReplacementVoter;
+use App\Shared\Domain\Tenant\TenantId;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use Override;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+/**
+ * @implements ProviderInterface<TeacherReplacementResource>
+ */
+final readonly class TeacherReplacementItemProvider implements ProviderInterface
+{
+    public function __construct(
+        private TeacherReplacementRepository $replacementRepository,
+        private TenantContext $tenantContext,
+        private AuthorizationCheckerInterface $authorizationChecker,
+    ) {
+    }
+
+    #[Override]
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): TeacherReplacementResource
+    {
+        if (!$this->authorizationChecker->isGranted(TeacherReplacementVoter::DELETE)) {
+            throw new AccessDeniedHttpException('Vous n\'êtes pas autorisé à terminer les remplacements.');
+        }
+
+        if (!$this->tenantContext->hasTenant()) {
+            throw new UnauthorizedHttpException('Bearer', 'Tenant non défini.');
+        }
+
+        /** @var string $id */
+        $id = $uriVariables['id'];
+        $tenantId = TenantId::fromString((string) $this->tenantContext->getCurrentTenantId());
+
+        $replacement = $this->replacementRepository->findById(
+            TeacherReplacementId::fromString($id),
+            $tenantId,
+        );
+
+        if ($replacement === null) {
+            throw new NotFoundHttpException('Remplacement non trouvé.');
+        }
+
+        return TeacherReplacementResource::fromDomain($replacement);
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Provider/TeacherReplacementsCollectionProvider.php b/backend/src/Scolarite/Infrastructure/Api/Provider/TeacherReplacementsCollectionProvider.php
new file mode 100644
index 0000000..2867651
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Provider/TeacherReplacementsCollectionProvider.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Provider;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+use App\Scolarite\Application\Query\GetActiveReplacements\GetActiveReplacementsHandler;
+use App\Scolarite\Application\Query\GetActiveReplacements\GetActiveReplacementsQuery;
+use App\Scolarite\Application\Query\GetActiveReplacements\ReplacementDto;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Security\TeacherReplacementVoter;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+
+use function array_map;
+
+use Override;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+/**
+ * @implements ProviderInterface<TeacherReplacementResource>
+ */
+final readonly class TeacherReplacementsCollectionProvider implements ProviderInterface
+{
+    public function __construct(
+        private GetActiveReplacementsHandler $handler,
+        private TenantContext $tenantContext,
+        private AuthorizationCheckerInterface $authorizationChecker,
+    ) {
+    }
+
+    /** @return array<TeacherReplacementResource> */
+    #[Override]
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): array
+    {
+        if (!$this->authorizationChecker->isGranted(TeacherReplacementVoter::VIEW)) {
+            throw new AccessDeniedHttpException('Vous n\'êtes pas autorisé à voir les remplacements.');
+        }
+
+        if (!$this->tenantContext->hasTenant()) {
+            throw new UnauthorizedHttpException('Bearer', 'Tenant non défini.');
+        }
+
+        $query = new GetActiveReplacementsQuery(
+            tenantId: (string) $this->tenantContext->getCurrentTenantId(),
+        );
+
+        $dtos = ($this->handler)($query);
+
+        return array_map(
+            static fn (ReplacementDto $dto) => TeacherReplacementResource::fromDto($dto),
+            $dtos,
+        );
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Resource/ReplacedClassResource.php b/backend/src/Scolarite/Infrastructure/Api/Resource/ReplacedClassResource.php
new file mode 100644
index 0000000..99f373f
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Resource/ReplacedClassResource.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Resource;
+
+use ApiPlatform\Metadata\ApiProperty;
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\GetCollection;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\ReplacedClassDto;
+use App\Scolarite\Infrastructure\Api\Provider\ReplacedClassesProvider;
+
+/**
+ * Classes/matières pour lesquelles l'enseignant connecté est remplaçant.
+ */
+#[ApiResource(
+    shortName: 'ReplacedClass',
+    operations: [
+        new GetCollection(
+            uriTemplate: '/me/replaced-classes',
+            provider: ReplacedClassesProvider::class,
+            name: 'get_replaced_classes',
+        ),
+    ],
+)]
+final class ReplacedClassResource
+{
+    #[ApiProperty(identifier: true)]
+    public string $id;
+
+    public string $replacementId;
+
+    public string $replacedTeacherId;
+
+    public string $classId;
+
+    public string $subjectId;
+
+    public string $className;
+
+    public string $subjectName;
+
+    public string $startDate;
+
+    public string $endDate;
+
+    public static function fromDto(ReplacedClassDto $dto): self
+    {
+        $resource = new self();
+        $resource->id = $dto->replacementId . '_' . $dto->classId . '_' . $dto->subjectId;
+        $resource->replacementId = $dto->replacementId;
+        $resource->replacedTeacherId = $dto->replacedTeacherId;
+        $resource->classId = $dto->classId;
+        $resource->subjectId = $dto->subjectId;
+        $resource->className = $dto->className;
+        $resource->subjectName = $dto->subjectName;
+        $resource->startDate = $dto->startDate->format('Y-m-d');
+        $resource->endDate = $dto->endDate->format('Y-m-d');
+
+        return $resource;
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Api/Resource/TeacherReplacementResource.php b/backend/src/Scolarite/Infrastructure/Api/Resource/TeacherReplacementResource.php
new file mode 100644
index 0000000..873a5e7
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Api/Resource/TeacherReplacementResource.php
@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Api\Resource;
+
+use ApiPlatform\Metadata\ApiProperty;
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\Delete;
+use ApiPlatform\Metadata\GetCollection;
+use ApiPlatform\Metadata\Post;
+use App\Scolarite\Application\Query\GetActiveReplacements\ReplacementDto;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Api\Processor\CreateTeacherReplacementProcessor;
+use App\Scolarite\Infrastructure\Api\Processor\EndTeacherReplacementProcessor;
+use App\Scolarite\Infrastructure\Api\Provider\TeacherReplacementItemProvider;
+use App\Scolarite\Infrastructure\Api\Provider\TeacherReplacementsCollectionProvider;
+use DateTimeImmutable;
+use Symfony\Component\Validator\Constraints as Assert;
+
+/**
+ * API Resource pour la gestion des remplacements enseignants.
+ *
+ * @see Story 2.9 - Désignation Remplaçants Temporaires
+ * @see FR9 - Désigner remplaçant temporaire
+ */
+#[ApiResource(
+    shortName: 'TeacherReplacement',
+    operations: [
+        new GetCollection(
+            uriTemplate: '/teacher-replacements',
+            provider: TeacherReplacementsCollectionProvider::class,
+            name: 'get_teacher_replacements',
+        ),
+        new Post(
+            uriTemplate: '/teacher-replacements',
+            processor: CreateTeacherReplacementProcessor::class,
+            validationContext: ['groups' => ['Default', 'create']],
+            name: 'create_teacher_replacement',
+        ),
+        new Delete(
+            uriTemplate: '/teacher-replacements/{id}',
+            provider: TeacherReplacementItemProvider::class,
+            processor: EndTeacherReplacementProcessor::class,
+            name: 'end_teacher_replacement',
+        ),
+    ],
+)]
+final class TeacherReplacementResource
+{
+    #[ApiProperty(identifier: true)]
+    public ?string $id = null;
+
+    #[Assert\NotBlank(message: 'L\'identifiant de l\'enseignant remplacé est requis.', groups: ['create'])]
+    public ?string $replacedTeacherId = null;
+
+    #[Assert\NotBlank(message: 'L\'identifiant du remplaçant est requis.', groups: ['create'])]
+    public ?string $replacementTeacherId = null;
+
+    #[Assert\NotBlank(message: 'La date de début est requise.', groups: ['create'])]
+    public ?string $startDate = null;
+
+    #[Assert\NotBlank(message: 'La date de fin est requise.', groups: ['create'])]
+    public ?string $endDate = null;
+
+    /** @var array<array{classId: string, subjectId: string}>|null */
+    #[Assert\NotBlank(message: 'Au moins une classe/matière est requise.', groups: ['create'])]
+    #[Assert\All(
+        constraints: [
+            new Assert\Collection(
+                fields: [
+                    'classId' => [
+                        new Assert\NotBlank(message: 'L\'identifiant de la classe est requis.', groups: ['create']),
+                        new Assert\Uuid(message: 'L\'identifiant de la classe doit être un UUID valide.', groups: ['create']),
+                    ],
+                    'subjectId' => [
+                        new Assert\NotBlank(message: 'L\'identifiant de la matière est requis.', groups: ['create']),
+                        new Assert\Uuid(message: 'L\'identifiant de la matière doit être un UUID valide.', groups: ['create']),
+                    ],
+                ],
+                allowExtraFields: false,
+                allowMissingFields: false,
+                groups: ['create'],
+            ),
+        ],
+        groups: ['create'],
+    )]
+    public ?array $classes = null;
+
+    public ?string $reason = null;
+
+    public ?string $status = null;
+
+    public ?DateTimeImmutable $createdAt = null;
+
+    public ?DateTimeImmutable $endedAt = null;
+
+    public static function fromDomain(TeacherReplacement $replacement): self
+    {
+        $resource = new self();
+        $resource->id = (string) $replacement->id;
+        $resource->replacedTeacherId = (string) $replacement->replacedTeacherId;
+        $resource->replacementTeacherId = (string) $replacement->replacementTeacherId;
+        $resource->startDate = $replacement->startDate->format('Y-m-d');
+        $resource->endDate = $replacement->endDate->format('Y-m-d');
+        $resource->classes = array_map(
+            static fn ($pair) => [
+                'classId' => (string) $pair->classId,
+                'subjectId' => (string) $pair->subjectId,
+            ],
+            $replacement->classes,
+        );
+        $resource->reason = $replacement->reason;
+        $resource->status = $replacement->status->value;
+        $resource->createdAt = $replacement->createdAt;
+        $resource->endedAt = $replacement->endedAt;
+
+        return $resource;
+    }
+
+    public static function fromDto(ReplacementDto $dto): self
+    {
+        $resource = new self();
+        $resource->id = $dto->id;
+        $resource->replacedTeacherId = $dto->replacedTeacherId;
+        $resource->replacementTeacherId = $dto->replacementTeacherId;
+        $resource->startDate = $dto->startDate->format('Y-m-d');
+        $resource->endDate = $dto->endDate->format('Y-m-d');
+        $resource->classes = $dto->classes;
+        $resource->reason = $dto->reason;
+        $resource->status = $dto->status;
+
+        return $resource;
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Console/EndExpiredReplacementsCommand.php b/backend/src/Scolarite/Infrastructure/Console/EndExpiredReplacementsCommand.php
new file mode 100644
index 0000000..546f3fb
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Console/EndExpiredReplacementsCommand.php
@@ -0,0 +1,115 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Console;
+
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementCommand;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementHandler;
+use App\Scolarite\Domain\Exception\RemplacementDejaTermineException;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+
+use function count;
+
+use Override;
+use Psr\Log\LoggerInterface;
+
+use function sprintf;
+
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+use Throwable;
+
+/**
+ * Termine automatiquement les remplacements dont la date de fin est dépassée.
+ *
+ * CRON: 0 0 * * * php bin/console app:end-expired-replacements
+ *
+ * @see Story 2.9 - AC3: Fin automatique remplacement
+ */
+#[AsCommand(
+    name: 'app:end-expired-replacements',
+    description: 'Termine les remplacements dont la date de fin est dépassée',
+)]
+final class EndExpiredReplacementsCommand extends Command
+{
+    public function __construct(
+        private readonly TeacherReplacementRepository $replacementRepository,
+        private readonly EndReplacementHandler $endReplacementHandler,
+        private readonly Clock $clock,
+        private readonly LoggerInterface $logger,
+    ) {
+        parent::__construct();
+    }
+
+    #[Override]
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $io = new SymfonyStyle($input, $output);
+        $io->title('Fin automatique des remplacements expirés');
+
+        $expiredReplacements = $this->replacementRepository->findExpired($this->clock->now());
+
+        if ($expiredReplacements === []) {
+            $io->success('Aucun remplacement expiré à traiter.');
+
+            return Command::SUCCESS;
+        }
+
+        $io->info(sprintf('%d remplacement(s) expiré(s) trouvé(s)', count($expiredReplacements)));
+
+        $endedCount = 0;
+
+        foreach ($expiredReplacements as $replacement) {
+            try {
+                ($this->endReplacementHandler)(new EndReplacementCommand(
+                    replacementId: (string) $replacement->id,
+                    tenantId: (string) $replacement->tenantId,
+                ));
+
+                $io->writeln(sprintf(
+                    '  ✅ Remplacement %s terminé (remplaçant: %s)',
+                    $replacement->id,
+                    $replacement->replacementTeacherId,
+                ));
+
+                $this->logger->info('Remplacement terminé automatiquement', [
+                    'replacement_id' => (string) $replacement->id,
+                    'tenant_id' => (string) $replacement->tenantId,
+                    'replaced_teacher_id' => (string) $replacement->replacedTeacherId,
+                    'replacement_teacher_id' => (string) $replacement->replacementTeacherId,
+                ]);
+
+                ++$endedCount;
+            } catch (RemplacementDejaTermineException $e) {
+                $io->warning(sprintf(
+                    '  ⚠ Remplacement %s déjà terminé, ignoré',
+                    $replacement->id,
+                ));
+
+                $this->logger->info('Remplacement déjà terminé, ignoré lors du traitement automatique', [
+                    'replacement_id' => (string) $replacement->id,
+                ]);
+            } catch (Throwable $e) {
+                $io->error(sprintf(
+                    'Erreur pour le remplacement %s : %s',
+                    $replacement->id,
+                    $e->getMessage(),
+                ));
+
+                $this->logger->error('Erreur lors de la terminaison automatique du remplacement', [
+                    'replacement_id' => (string) $replacement->id,
+                    'error' => $e->getMessage(),
+                ]);
+            }
+        }
+
+        $io->success(sprintf('%d remplacement(s) terminé(s) avec succès.', $endedCount));
+
+        return Command::SUCCESS;
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Persistence/Doctrine/DoctrineTeacherReplacementRepository.php b/backend/src/Scolarite/Infrastructure/Persistence/Doctrine/DoctrineTeacherReplacementRepository.php
new file mode 100644
index 0000000..b499e68
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Persistence/Doctrine/DoctrineTeacherReplacementRepository.php
@@ -0,0 +1,317 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Persistence\Doctrine;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Exception\RemplacementNotFoundException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Tenant\TenantId;
+
+use function count;
+
+use DateTimeImmutable;
+use Doctrine\DBAL\Connection;
+use Override;
+
+final readonly class DoctrineTeacherReplacementRepository implements TeacherReplacementRepository
+{
+    public function __construct(
+        private Connection $connection,
+    ) {
+    }
+
+    #[Override]
+    public function save(TeacherReplacement $replacement): void
+    {
+        $this->connection->executeStatement(
+            'INSERT INTO teacher_replacements (id, tenant_id, replaced_teacher_id, replacement_teacher_id, start_date, end_date, status, reason, created_by, created_at, ended_at, updated_at)
+             VALUES (:id, :tenant_id, :replaced_teacher_id, :replacement_teacher_id, :start_date, :end_date, :status, :reason, :created_by, :created_at, :ended_at, :updated_at)
+             ON CONFLICT (id) DO UPDATE SET
+                 status = EXCLUDED.status,
+                 ended_at = EXCLUDED.ended_at,
+                 updated_at = EXCLUDED.updated_at',
+            [
+                'id' => (string) $replacement->id,
+                'tenant_id' => (string) $replacement->tenantId,
+                'replaced_teacher_id' => (string) $replacement->replacedTeacherId,
+                'replacement_teacher_id' => (string) $replacement->replacementTeacherId,
+                'start_date' => $replacement->startDate->format('Y-m-d'),
+                'end_date' => $replacement->endDate->format('Y-m-d'),
+                'status' => $replacement->status->value,
+                'reason' => $replacement->reason,
+                'created_by' => (string) $replacement->createdBy,
+                'created_at' => $replacement->createdAt->format(DateTimeImmutable::ATOM),
+                'ended_at' => $replacement->endedAt?->format(DateTimeImmutable::ATOM),
+                'updated_at' => $replacement->updatedAt->format(DateTimeImmutable::ATOM),
+            ],
+        );
+
+        // Upsert replacement_classes
+        $this->connection->executeStatement(
+            'DELETE FROM replacement_classes WHERE replacement_id = :replacement_id',
+            ['replacement_id' => (string) $replacement->id],
+        );
+
+        foreach ($replacement->classes as $pair) {
+            $this->connection->executeStatement(
+                'INSERT INTO replacement_classes (replacement_id, class_id, subject_id) VALUES (:replacement_id, :class_id, :subject_id)',
+                [
+                    'replacement_id' => (string) $replacement->id,
+                    'class_id' => (string) $pair->classId,
+                    'subject_id' => (string) $pair->subjectId,
+                ],
+            );
+        }
+    }
+
+    #[Override]
+    public function get(TeacherReplacementId $id, TenantId $tenantId): TeacherReplacement
+    {
+        $replacement = $this->findById($id, $tenantId);
+
+        if ($replacement === null) {
+            throw RemplacementNotFoundException::withId($id);
+        }
+
+        return $replacement;
+    }
+
+    #[Override]
+    public function findById(TeacherReplacementId $id, TenantId $tenantId): ?TeacherReplacement
+    {
+        $row = $this->connection->fetchAssociative(
+            'SELECT * FROM teacher_replacements WHERE id = :id AND tenant_id = :tenant_id',
+            ['id' => (string) $id, 'tenant_id' => (string) $tenantId],
+        );
+
+        if ($row === false) {
+            return null;
+        }
+
+        return $this->hydrate($row);
+    }
+
+    #[Override]
+    public function findActiveReplacement(
+        UserId $replacementTeacherId,
+        ClassId $classId,
+        SubjectId $subjectId,
+        DateTimeImmutable $at,
+        TenantId $tenantId,
+    ): ?TeacherReplacement {
+        $row = $this->connection->fetchAssociative(
+            'SELECT tr.* FROM teacher_replacements tr
+             JOIN replacement_classes rc ON rc.replacement_id = tr.id
+             WHERE tr.tenant_id = :tenant_id
+             AND tr.replacement_teacher_id = :replacement_teacher_id
+             AND rc.class_id = :class_id
+             AND rc.subject_id = :subject_id
+             AND tr.status = :status
+             AND tr.start_date <= :at
+             AND tr.end_date >= :at',
+            [
+                'tenant_id' => (string) $tenantId,
+                'replacement_teacher_id' => (string) $replacementTeacherId,
+                'class_id' => (string) $classId,
+                'subject_id' => (string) $subjectId,
+                'status' => ReplacementStatus::ACTIVE->value,
+                'at' => $at->format('Y-m-d'),
+            ],
+        );
+
+        if ($row === false) {
+            return null;
+        }
+
+        return $this->hydrate($row);
+    }
+
+    #[Override]
+    public function findActiveByTenant(TenantId $tenantId, DateTimeImmutable $at): array
+    {
+        $rows = $this->connection->fetchAllAssociative(
+            'SELECT * FROM teacher_replacements
+             WHERE tenant_id = :tenant_id
+             AND status = :status
+             AND start_date <= :at
+             AND end_date >= :at
+             ORDER BY start_date ASC',
+            [
+                'tenant_id' => (string) $tenantId,
+                'status' => ReplacementStatus::ACTIVE->value,
+                'at' => $at->format('Y-m-d'),
+            ],
+        );
+
+        return $this->hydrateMany($rows);
+    }
+
+    #[Override]
+    public function findActiveByReplacementTeacher(
+        UserId $replacementTeacherId,
+        TenantId $tenantId,
+        DateTimeImmutable $at,
+    ): array {
+        $rows = $this->connection->fetchAllAssociative(
+            'SELECT * FROM teacher_replacements
+             WHERE replacement_teacher_id = :replacement_teacher_id
+             AND tenant_id = :tenant_id
+             AND status = :status
+             AND start_date <= :at
+             AND end_date >= :at
+             ORDER BY created_at ASC',
+            [
+                'replacement_teacher_id' => (string) $replacementTeacherId,
+                'tenant_id' => (string) $tenantId,
+                'status' => ReplacementStatus::ACTIVE->value,
+                'at' => $at->format('Y-m-d'),
+            ],
+        );
+
+        return $this->hydrateMany($rows);
+    }
+
+    #[Override]
+    public function findExpired(DateTimeImmutable $at): array
+    {
+        $rows = $this->connection->fetchAllAssociative(
+            'SELECT * FROM teacher_replacements
+             WHERE status = :status
+             AND end_date < :at
+             ORDER BY end_date ASC',
+            [
+                'status' => ReplacementStatus::ACTIVE->value,
+                'at' => $at->format('Y-m-d'),
+            ],
+        );
+
+        return $this->hydrateMany($rows);
+    }
+
+    /** @return array<ClassSubjectPair> */
+    private function loadClasses(string $replacementId): array
+    {
+        return $this->loadClassesBatch([$replacementId])[$replacementId] ?? [];
+    }
+
+    /**
+     * @param list<string> $replacementIds
+     *
+     * @return array<string, list<ClassSubjectPair>>
+     */
+    private function loadClassesBatch(array $replacementIds): array
+    {
+        if ($replacementIds === []) {
+            return [];
+        }
+
+        $placeholders = implode(', ', array_fill(0, count($replacementIds), '?'));
+        $rows = $this->connection->fetchAllAssociative(
+            "SELECT replacement_id, class_id, subject_id FROM replacement_classes WHERE replacement_id IN ($placeholders)",
+            array_values($replacementIds),
+        );
+
+        $grouped = [];
+        foreach ($rows as $row) {
+            /** @var string $replacementId */
+            $replacementId = $row['replacement_id'];
+            /** @var string $classId */
+            $classId = $row['class_id'];
+            /** @var string $subjectId */
+            $subjectId = $row['subject_id'];
+
+            $grouped[$replacementId][] = new ClassSubjectPair(
+                ClassId::fromString($classId),
+                SubjectId::fromString($subjectId),
+            );
+        }
+
+        return $grouped;
+    }
+
+    /**
+     * @param list<array<string, mixed>> $rows
+     *
+     * @return list<TeacherReplacement>
+     */
+    private function hydrateMany(array $rows): array
+    {
+        if ($rows === []) {
+            return [];
+        }
+
+        $ids = array_map(static function (array $row): string {
+            /** @var string $id */
+            $id = $row['id'];
+
+            return $id;
+        }, $rows);
+        $classesByReplacement = $this->loadClassesBatch($ids);
+
+        return array_map(
+            function (array $row) use ($classesByReplacement) {
+                /** @var string $id */
+                $id = $row['id'];
+
+                return $this->hydrate($row, $classesByReplacement[$id] ?? []);
+            },
+            $rows,
+        );
+    }
+
+    /**
+     * @param array<string, mixed>         $row
+     * @param array<ClassSubjectPair>|null $classes Pre-loaded classes (null = load individually)
+     */
+    private function hydrate(array $row, ?array $classes = null): TeacherReplacement
+    {
+        /** @var string $id */
+        $id = $row['id'];
+        /** @var string $tenantId */
+        $tenantId = $row['tenant_id'];
+        /** @var string $replacedTeacherId */
+        $replacedTeacherId = $row['replaced_teacher_id'];
+        /** @var string $replacementTeacherId */
+        $replacementTeacherId = $row['replacement_teacher_id'];
+        /** @var string $startDate */
+        $startDate = $row['start_date'];
+        /** @var string $endDate */
+        $endDate = $row['end_date'];
+        /** @var string $status */
+        $status = $row['status'];
+        /** @var string|null $reason */
+        $reason = $row['reason'];
+        /** @var string $createdBy */
+        $createdBy = $row['created_by'];
+        /** @var string $createdAt */
+        $createdAt = $row['created_at'];
+        /** @var string|null $endedAt */
+        $endedAt = $row['ended_at'];
+        /** @var string $updatedAt */
+        $updatedAt = $row['updated_at'];
+
+        return TeacherReplacement::reconstitute(
+            id: TeacherReplacementId::fromString($id),
+            tenantId: TenantId::fromString($tenantId),
+            replacedTeacherId: UserId::fromString($replacedTeacherId),
+            replacementTeacherId: UserId::fromString($replacementTeacherId),
+            startDate: new DateTimeImmutable($startDate),
+            endDate: new DateTimeImmutable($endDate),
+            status: ReplacementStatus::from($status),
+            classes: $classes ?? $this->loadClasses($id),
+            reason: $reason,
+            createdBy: UserId::fromString($createdBy),
+            createdAt: new DateTimeImmutable($createdAt),
+            endedAt: $endedAt !== null ? new DateTimeImmutable($endedAt) : null,
+            updatedAt: new DateTimeImmutable($updatedAt),
+        );
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Persistence/InMemory/InMemoryTeacherReplacementRepository.php b/backend/src/Scolarite/Infrastructure/Persistence/InMemory/InMemoryTeacherReplacementRepository.php
new file mode 100644
index 0000000..51236a2
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Persistence/InMemory/InMemoryTeacherReplacementRepository.php
@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Persistence\InMemory;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Exception\RemplacementNotFoundException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Scolarite\Domain\Repository\TeacherReplacementRepository;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use Override;
+
+final class InMemoryTeacherReplacementRepository implements TeacherReplacementRepository
+{
+    /** @var array<string, TeacherReplacement> */
+    private array $byId = [];
+
+    #[Override]
+    public function save(TeacherReplacement $replacement): void
+    {
+        $this->byId[(string) $replacement->id] = $replacement;
+    }
+
+    #[Override]
+    public function get(TeacherReplacementId $id, TenantId $tenantId): TeacherReplacement
+    {
+        $replacement = $this->findById($id, $tenantId);
+
+        if ($replacement === null) {
+            throw RemplacementNotFoundException::withId($id);
+        }
+
+        return $replacement;
+    }
+
+    #[Override]
+    public function findById(TeacherReplacementId $id, TenantId $tenantId): ?TeacherReplacement
+    {
+        $replacement = $this->byId[(string) $id] ?? null;
+
+        if ($replacement !== null && !$replacement->tenantId->equals($tenantId)) {
+            return null;
+        }
+
+        return $replacement;
+    }
+
+    #[Override]
+    public function findActiveReplacement(
+        UserId $replacementTeacherId,
+        ClassId $classId,
+        SubjectId $subjectId,
+        DateTimeImmutable $at,
+        TenantId $tenantId,
+    ): ?TeacherReplacement {
+        $pair = new ClassSubjectPair($classId, $subjectId);
+
+        foreach ($this->byId as $replacement) {
+            if ($replacement->tenantId->equals($tenantId)
+                && $replacement->replacementTeacherId->equals($replacementTeacherId)
+                && $replacement->isActive($at)
+                && $replacement->couvreClasseMatiere($pair)
+            ) {
+                return $replacement;
+            }
+        }
+
+        return null;
+    }
+
+    #[Override]
+    public function findActiveByTenant(TenantId $tenantId, DateTimeImmutable $at): array
+    {
+        return array_values(array_filter(
+            $this->byId,
+            static fn (TeacherReplacement $r) => $r->tenantId->equals($tenantId)
+                && $r->isActive($at),
+        ));
+    }
+
+    #[Override]
+    public function findActiveByReplacementTeacher(
+        UserId $replacementTeacherId,
+        TenantId $tenantId,
+        DateTimeImmutable $at,
+    ): array {
+        return array_values(array_filter(
+            $this->byId,
+            static fn (TeacherReplacement $r) => $r->tenantId->equals($tenantId)
+                && $r->replacementTeacherId->equals($replacementTeacherId)
+                && $r->isActive($at),
+        ));
+    }
+
+    #[Override]
+    public function findExpired(DateTimeImmutable $at): array
+    {
+        return array_values(array_filter(
+            $this->byId,
+            static fn (TeacherReplacement $r) => $r->status === ReplacementStatus::ACTIVE
+                && $r->isExpired($at),
+        ));
+    }
+}
diff --git a/backend/src/Scolarite/Infrastructure/Security/TeacherReplacementVoter.php b/backend/src/Scolarite/Infrastructure/Security/TeacherReplacementVoter.php
new file mode 100644
index 0000000..7d8848d
--- /dev/null
+++ b/backend/src/Scolarite/Infrastructure/Security/TeacherReplacementVoter.php
@@ -0,0 +1,132 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Infrastructure\Security;
+
+use App\Administration\Domain\Model\User\Role;
+use App\Administration\Infrastructure\Security\SecurityUser;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+
+use function in_array;
+
+use Override;
+use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
+use Symfony\Component\Security\Core\Authorization\Voter\Vote;
+use Symfony\Component\Security\Core\Authorization\Voter\Voter;
+
+/**
+ * Voter pour les autorisations sur les remplacements enseignants.
+ *
+ * Règles d'accès :
+ * - ADMIN et SUPER_ADMIN : accès complet (CRUD)
+ * - ENSEIGNANT : lecture seule (ses propres remplacements actifs/passifs)
+ * - Autres rôles : pas d'accès
+ *
+ * @extends Voter<string, TeacherReplacement|null>
+ */
+final class TeacherReplacementVoter extends Voter
+{
+    public const string VIEW = 'TEACHER_REPLACEMENT_VIEW';
+    public const string CREATE = 'TEACHER_REPLACEMENT_CREATE';
+    public const string DELETE = 'TEACHER_REPLACEMENT_DELETE';
+
+    private const array SUPPORTED_ATTRIBUTES = [
+        self::VIEW,
+        self::CREATE,
+        self::DELETE,
+    ];
+
+    #[Override]
+    protected function supports(string $attribute, mixed $subject): bool
+    {
+        if (!in_array($attribute, self::SUPPORTED_ATTRIBUTES, true)) {
+            return false;
+        }
+
+        if ($subject === null) {
+            return true;
+        }
+
+        return $subject instanceof TeacherReplacement;
+    }
+
+    #[Override]
+    protected function voteOnAttribute(string $attribute, mixed $subject, TokenInterface $token, ?Vote $vote = null): bool
+    {
+        $user = $token->getUser();
+
+        if (!$user instanceof SecurityUser) {
+            return false;
+        }
+
+        $roles = $user->getRoles();
+
+        return match ($attribute) {
+            self::VIEW => $this->canView($roles, $user, $subject),
+            self::CREATE => $this->canCreate($roles),
+            self::DELETE => $this->canDelete($roles),
+            default => false,
+        };
+    }
+
+    /** @param string[] $roles */
+    private function canView(array $roles, SecurityUser $user, mixed $subject): bool
+    {
+        if ($this->hasAnyRole($roles, [
+            Role::SUPER_ADMIN->value,
+            Role::ADMIN->value,
+        ])) {
+            return true;
+        }
+
+        if ($this->hasAnyRole($roles, [Role::PROF->value])) {
+            return $this->isInvolvedTeacher($user, $subject);
+        }
+
+        return false;
+    }
+
+    private function isInvolvedTeacher(SecurityUser $user, mixed $subject): bool
+    {
+        if (!$subject instanceof TeacherReplacement) {
+            return false;
+        }
+
+        return (string) $subject->replacedTeacherId === $user->userId()
+            || (string) $subject->replacementTeacherId === $user->userId();
+    }
+
+    /** @param string[] $roles */
+    private function canCreate(array $roles): bool
+    {
+        return $this->hasAnyRole($roles, [
+            Role::SUPER_ADMIN->value,
+            Role::ADMIN->value,
+        ]);
+    }
+
+    /** @param string[] $roles */
+    private function canDelete(array $roles): bool
+    {
+        return $this->hasAnyRole($roles, [
+            Role::SUPER_ADMIN->value,
+            Role::ADMIN->value,
+        ]);
+    }
+
+    /**
+     * @param string[] $userRoles
+     * @param string[] $allowedRoles
+     */
+    private function hasAnyRole(array $userRoles, array $allowedRoles): bool
+    {
+        foreach ($userRoles as $role) {
+            if (in_array($role, $allowedRoles, true)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementHandlerTest.php b/backend/tests/Unit/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementHandlerTest.php
new file mode 100644
index 0000000..ea100ff
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Application/Command/DesignateReplacement/DesignateReplacementHandlerTest.php
@@ -0,0 +1,271 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Command\DesignateReplacement;
+
+use App\Administration\Domain\Exception\TenantMismatchException;
+use App\Administration\Domain\Exception\UserNotFoundException;
+use App\Administration\Domain\Model\User\Email;
+use App\Administration\Domain\Model\User\Role;
+use App\Administration\Domain\Model\User\StatutCompte;
+use App\Administration\Domain\Model\User\User;
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemoryUserRepository;
+use App\Scolarite\Application\Command\DesignateReplacement\DesignateReplacementCommand;
+use App\Scolarite\Application\Command\DesignateReplacement\DesignateReplacementHandler;
+use App\Scolarite\Domain\Exception\DatesRemplacementInvalidesException;
+use App\Scolarite\Domain\Exception\RemplacementSameTeacherException;
+use App\Scolarite\Domain\Exception\UtilisateurNonEnseignantException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class DesignateReplacementHandlerTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+    private const string OTHER_TENANT_ID = '550e8400-e29b-41d4-a716-446655440002';
+    private const string OTHER_TENANT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440012';
+    private const string ADMIN_USER_ID = '550e8400-e29b-41d4-a716-446655440050';
+
+    private InMemoryTeacherReplacementRepository $replacementRepository;
+    private InMemoryUserRepository $userRepository;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->replacementRepository = new InMemoryTeacherReplacementRepository();
+        $this->userRepository = new InMemoryUserRepository();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-02-15 10:00:00');
+            }
+        };
+
+        $this->seedTestData();
+    }
+
+    #[Test]
+    public function itCreatesReplacementSuccessfully(): void
+    {
+        $handler = $this->createHandler();
+        $command = $this->createCommand();
+
+        $replacement = $handler($command);
+
+        self::assertNotEmpty((string) $replacement->id);
+        self::assertSame(ReplacementStatus::ACTIVE, $replacement->status);
+        self::assertNull($replacement->endedAt);
+    }
+
+    #[Test]
+    public function itPersistsReplacementInRepository(): void
+    {
+        $handler = $this->createHandler();
+        $command = $this->createCommand();
+
+        $created = $handler($command);
+
+        $replacement = $this->replacementRepository->get(
+            TeacherReplacementId::fromString((string) $created->id),
+            TenantId::fromString(self::TENANT_ID),
+        );
+
+        self::assertSame(ReplacementStatus::ACTIVE, $replacement->status);
+        self::assertCount(1, $replacement->classes);
+    }
+
+    #[Test]
+    public function itSetsAllPropertiesCorrectly(): void
+    {
+        $handler = $this->createHandler();
+        $command = $this->createCommand();
+
+        $replacement = $handler($command);
+
+        self::assertTrue($replacement->replacedTeacherId->equals(UserId::fromString(self::REPLACED_TEACHER_ID)));
+        self::assertTrue($replacement->replacementTeacherId->equals(UserId::fromString(self::REPLACEMENT_TEACHER_ID)));
+        self::assertEquals(new DateTimeImmutable('2026-03-01'), $replacement->startDate);
+        self::assertEquals(new DateTimeImmutable('2026-03-31'), $replacement->endDate);
+        self::assertSame('Congé maladie', $replacement->reason);
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacedTeacherDoesNotExist(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(UserNotFoundException::class);
+        $handler($this->createCommand(replacedTeacherId: '550e8400-e29b-41d4-a716-446655440088'));
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacementTeacherDoesNotExist(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(UserNotFoundException::class);
+        $handler($this->createCommand(replacementTeacherId: '550e8400-e29b-41d4-a716-446655440088'));
+    }
+
+    #[Test]
+    public function itThrowsWhenSameTeacher(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(RemplacementSameTeacherException::class);
+        $handler($this->createCommand(replacementTeacherId: self::REPLACED_TEACHER_ID));
+    }
+
+    #[Test]
+    public function itThrowsWhenEndDateBeforeStartDate(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(DatesRemplacementInvalidesException::class);
+        $handler($this->createCommand(startDate: '2026-03-31', endDate: '2026-03-01'));
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacedTeacherBelongsToDifferentTenant(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(TenantMismatchException::class);
+        $handler($this->createCommand(replacedTeacherId: self::OTHER_TENANT_TEACHER_ID));
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacementTeacherBelongsToDifferentTenant(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(TenantMismatchException::class);
+        $handler($this->createCommand(replacementTeacherId: self::OTHER_TENANT_TEACHER_ID));
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacedTeacherIsNotATeacher(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(UtilisateurNonEnseignantException::class);
+        $handler($this->createCommand(replacedTeacherId: self::ADMIN_USER_ID));
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacementTeacherIsNotATeacher(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(UtilisateurNonEnseignantException::class);
+        $handler($this->createCommand(replacementTeacherId: self::ADMIN_USER_ID));
+    }
+
+    private function seedTestData(): void
+    {
+        $tenantId = TenantId::fromString(self::TENANT_ID);
+
+        $replacedTeacher = User::reconstitute(
+            id: UserId::fromString(self::REPLACED_TEACHER_ID),
+            email: new Email('replaced@example.com'),
+            roles: [Role::PROF],
+            tenantId: $tenantId,
+            schoolName: 'École Test',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($replacedTeacher);
+
+        $replacementTeacher = User::reconstitute(
+            id: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            email: new Email('replacement@example.com'),
+            roles: [Role::PROF],
+            tenantId: $tenantId,
+            schoolName: 'École Test',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($replacementTeacher);
+
+        // Enseignant d'un autre tenant
+        $otherTenantTeacher = User::reconstitute(
+            id: UserId::fromString(self::OTHER_TENANT_TEACHER_ID),
+            email: new Email('other-tenant@example.com'),
+            roles: [Role::PROF],
+            tenantId: TenantId::fromString(self::OTHER_TENANT_ID),
+            schoolName: 'Autre École',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($otherTenantTeacher);
+
+        // Utilisateur admin (pas enseignant) dans le même tenant
+        $adminUser = User::reconstitute(
+            id: UserId::fromString(self::ADMIN_USER_ID),
+            email: new Email('admin@example.com'),
+            roles: [Role::ADMIN],
+            tenantId: $tenantId,
+            schoolName: 'École Test',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($adminUser);
+    }
+
+    private function createHandler(): DesignateReplacementHandler
+    {
+        return new DesignateReplacementHandler(
+            $this->replacementRepository,
+            $this->userRepository,
+            $this->clock,
+        );
+    }
+
+    private function createCommand(
+        ?string $replacedTeacherId = null,
+        ?string $replacementTeacherId = null,
+        ?string $startDate = null,
+        ?string $endDate = null,
+    ): DesignateReplacementCommand {
+        return new DesignateReplacementCommand(
+            tenantId: self::TENANT_ID,
+            replacedTeacherId: $replacedTeacherId ?? self::REPLACED_TEACHER_ID,
+            replacementTeacherId: $replacementTeacherId ?? self::REPLACEMENT_TEACHER_ID,
+            startDate: $startDate ?? '2026-03-01',
+            endDate: $endDate ?? '2026-03-31',
+            classes: [
+                ['classId' => self::CLASS_ID, 'subjectId' => self::SUBJECT_ID],
+            ],
+            reason: 'Congé maladie',
+            createdBy: self::CREATED_BY_ID,
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Application/Command/EndReplacement/EndReplacementHandlerTest.php b/backend/tests/Unit/Scolarite/Application/Command/EndReplacement/EndReplacementHandlerTest.php
new file mode 100644
index 0000000..54d2ce2
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Application/Command/EndReplacement/EndReplacementHandlerTest.php
@@ -0,0 +1,120 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Command\EndReplacement;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementCommand;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementHandler;
+use App\Scolarite\Domain\Exception\RemplacementDejaTermineException;
+use App\Scolarite\Domain\Exception\RemplacementNotFoundException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class EndReplacementHandlerTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $replacementRepository;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->replacementRepository = new InMemoryTeacherReplacementRepository();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-03-15 10:00:00');
+            }
+        };
+    }
+
+    #[Test]
+    public function itEndsReplacementSuccessfully(): void
+    {
+        $replacement = $this->createAndSaveReplacement();
+        $handler = $this->createHandler();
+
+        $handler(new EndReplacementCommand(
+            replacementId: (string) $replacement->id,
+            tenantId: self::TENANT_ID,
+        ));
+
+        $ended = $this->replacementRepository->get($replacement->id, TenantId::fromString(self::TENANT_ID));
+        self::assertSame(ReplacementStatus::ENDED, $ended->status);
+        self::assertNotNull($ended->endedAt);
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacementNotFound(): void
+    {
+        $handler = $this->createHandler();
+
+        $this->expectException(RemplacementNotFoundException::class);
+        $handler(new EndReplacementCommand(
+            replacementId: '550e8400-e29b-41d4-a716-446655440088',
+            tenantId: self::TENANT_ID,
+        ));
+    }
+
+    #[Test]
+    public function itThrowsWhenReplacementAlreadyEnded(): void
+    {
+        $replacement = $this->createAndSaveReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-10'));
+        $this->replacementRepository->save($replacement);
+
+        $handler = $this->createHandler();
+
+        $this->expectException(RemplacementDejaTermineException::class);
+        $handler(new EndReplacementCommand(
+            replacementId: (string) $replacement->id,
+            tenantId: self::TENANT_ID,
+        ));
+    }
+
+    private function createAndSaveReplacement(): TeacherReplacement
+    {
+        $replacement = TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString('550e8400-e29b-41d4-a716-446655440020'),
+                    SubjectId::fromString('550e8400-e29b-41d4-a716-446655440030'),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+
+        $this->replacementRepository->save($replacement);
+
+        return $replacement;
+    }
+
+    private function createHandler(): EndReplacementHandler
+    {
+        return new EndReplacementHandler(
+            $this->replacementRepository,
+            $this->clock,
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsHandlerTest.php b/backend/tests/Unit/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsHandlerTest.php
new file mode 100644
index 0000000..3cfab97
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Application/Query/GetActiveReplacements/GetActiveReplacementsHandlerTest.php
@@ -0,0 +1,172 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Query\GetActiveReplacements;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Query\GetActiveReplacements\GetActiveReplacementsHandler;
+use App\Scolarite\Application\Query\GetActiveReplacements\GetActiveReplacementsQuery;
+use App\Scolarite\Application\Query\GetActiveReplacements\ReplacementDto;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class GetActiveReplacementsHandlerTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string OTHER_TENANT_ID = '550e8400-e29b-41d4-a716-446655440002';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $repository;
+    private DateTimeImmutable $now;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+        $this->now = new DateTimeImmutable('2026-03-15 10:00:00');
+    }
+
+    #[Test]
+    public function itReturnsActiveReplacementsForTenant(): void
+    {
+        $this->saveActiveReplacement();
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetActiveReplacementsQuery(self::TENANT_ID));
+
+        self::assertCount(1, $result);
+        self::assertContainsOnlyInstancesOf(ReplacementDto::class, $result);
+    }
+
+    #[Test]
+    public function itReturnsEmptyArrayWhenNoneExist(): void
+    {
+        $handler = $this->createHandler();
+        $result = $handler(new GetActiveReplacementsQuery(self::TENANT_ID));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itMapsCorrectlyToDtos(): void
+    {
+        $replacement = $this->saveActiveReplacement();
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetActiveReplacementsQuery(self::TENANT_ID));
+
+        self::assertCount(1, $result);
+
+        $dto = $result[0];
+        self::assertSame((string) $replacement->id, $dto->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $dto->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $dto->replacementTeacherId);
+        self::assertEquals(new DateTimeImmutable('2026-03-01'), $dto->startDate);
+        self::assertEquals(new DateTimeImmutable('2026-03-31'), $dto->endDate);
+        self::assertSame(ReplacementStatus::ACTIVE->value, $dto->status);
+        self::assertSame('Congé maladie', $dto->reason);
+        self::assertCount(1, $dto->classes);
+        self::assertSame(self::CLASS_ID, $dto->classes[0]['classId']);
+        self::assertSame(self::SUBJECT_ID, $dto->classes[0]['subjectId']);
+    }
+
+    #[Test]
+    public function itFiltersOutExpiredReplacements(): void
+    {
+        $this->saveReplacement(
+            startDate: new DateTimeImmutable('2026-01-01'),
+            endDate: new DateTimeImmutable('2026-02-01'),
+        );
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetActiveReplacementsQuery(self::TENANT_ID));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itFiltersOutEndedReplacements(): void
+    {
+        $replacement = $this->saveActiveReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-10'));
+        $this->repository->save($replacement);
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetActiveReplacementsQuery(self::TENANT_ID));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itDoesNotReturnReplacementsFromOtherTenants(): void
+    {
+        $this->saveReplacement(tenantId: self::OTHER_TENANT_ID);
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetActiveReplacementsQuery(self::TENANT_ID));
+
+        self::assertSame([], $result);
+    }
+
+    private function saveActiveReplacement(): TeacherReplacement
+    {
+        return $this->saveReplacement();
+    }
+
+    private function saveReplacement(
+        ?string $tenantId = null,
+        ?DateTimeImmutable $startDate = null,
+        ?DateTimeImmutable $endDate = null,
+    ): TeacherReplacement {
+        $replacement = TeacherReplacement::designer(
+            tenantId: TenantId::fromString($tenantId ?? self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: $startDate ?? new DateTimeImmutable('2026-03-01'),
+            endDate: $endDate ?? new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: 'Congé maladie',
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+
+        $this->repository->save($replacement);
+
+        return $replacement;
+    }
+
+    private function createHandler(): GetActiveReplacementsHandler
+    {
+        $now = $this->now;
+        $clock = new class($now) implements Clock {
+            public function __construct(private readonly DateTimeImmutable $now)
+            {
+            }
+
+            public function now(): DateTimeImmutable
+            {
+                return $this->now;
+            }
+        };
+
+        return new GetActiveReplacementsHandler($this->repository, $clock);
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Application/Query/GetActiveReplacements/ReplacementDtoTest.php b/backend/tests/Unit/Scolarite/Application/Query/GetActiveReplacements/ReplacementDtoTest.php
new file mode 100644
index 0000000..a017563
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Application/Query/GetActiveReplacements/ReplacementDtoTest.php
@@ -0,0 +1,126 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Query\GetActiveReplacements;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Query\GetActiveReplacements\ReplacementDto;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class ReplacementDtoTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    #[Test]
+    public function fromDomainCreatesCorrectDto(): void
+    {
+        $replacement = $this->createReplacement();
+
+        $dto = ReplacementDto::fromDomain($replacement);
+
+        self::assertSame((string) $replacement->id, $dto->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $dto->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $dto->replacementTeacherId);
+        self::assertEquals(new DateTimeImmutable('2026-03-01'), $dto->startDate);
+        self::assertEquals(new DateTimeImmutable('2026-03-31'), $dto->endDate);
+        self::assertSame(ReplacementStatus::ACTIVE->value, $dto->status);
+        self::assertSame('Congé maladie', $dto->reason);
+    }
+
+    #[Test]
+    public function fromDomainPreservesAllClassSubjectPairs(): void
+    {
+        $replacement = $this->createReplacementWithMultipleClasses();
+
+        $dto = ReplacementDto::fromDomain($replacement);
+
+        self::assertCount(2, $dto->classes);
+        self::assertSame(self::CLASS_ID, $dto->classes[0]['classId']);
+        self::assertSame(self::SUBJECT_ID, $dto->classes[0]['subjectId']);
+        self::assertSame('550e8400-e29b-41d4-a716-446655440021', $dto->classes[1]['classId']);
+        self::assertSame('550e8400-e29b-41d4-a716-446655440031', $dto->classes[1]['subjectId']);
+    }
+
+    #[Test]
+    public function fromDomainPreservesNullReason(): void
+    {
+        $replacement = TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+
+        $dto = ReplacementDto::fromDomain($replacement);
+
+        self::assertNull($dto->reason);
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: 'Congé maladie',
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+
+    private function createReplacementWithMultipleClasses(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+                new ClassSubjectPair(
+                    ClassId::fromString('550e8400-e29b-41d4-a716-446655440021'),
+                    SubjectId::fromString('550e8400-e29b-41d4-a716-446655440031'),
+                ),
+            ],
+            reason: 'Congé maladie',
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherHandlerTest.php b/backend/tests/Unit/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherHandlerTest.php
new file mode 100644
index 0000000..217f7fc
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Application/Query/GetReplacedClassesForTeacher/GetReplacedClassesForTeacherHandlerTest.php
@@ -0,0 +1,274 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Query\GetReplacedClassesForTeacher;
+
+use App\Administration\Domain\Model\SchoolClass\AcademicYearId;
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\SchoolClass\ClassName;
+use App\Administration\Domain\Model\SchoolClass\ClassStatus;
+use App\Administration\Domain\Model\SchoolClass\SchoolClass;
+use App\Administration\Domain\Model\SchoolClass\SchoolId;
+use App\Administration\Domain\Model\Subject\Subject;
+use App\Administration\Domain\Model\Subject\SubjectCode;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\Subject\SubjectName;
+use App\Administration\Domain\Model\Subject\SubjectStatus;
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemoryClassRepository;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemorySubjectRepository;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\GetReplacedClassesForTeacherHandler;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\GetReplacedClassesForTeacherQuery;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\ReplacedClassDto;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class GetReplacedClassesForTeacherHandlerTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string OTHER_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440012';
+    private const string CLASS_ID_1 = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID_1 = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CLASS_ID_2 = '550e8400-e29b-41d4-a716-446655440021';
+    private const string SUBJECT_ID_2 = '550e8400-e29b-41d4-a716-446655440031';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+    private const string SCHOOL_ID = '550e8400-e29b-41d4-a716-446655440040';
+    private const string ACADEMIC_YEAR_ID = '550e8400-e29b-41d4-a716-446655440041';
+
+    private InMemoryTeacherReplacementRepository $repository;
+    private InMemoryClassRepository $classRepository;
+    private InMemorySubjectRepository $subjectRepository;
+    private DateTimeImmutable $now;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+        $this->classRepository = new InMemoryClassRepository();
+        $this->subjectRepository = new InMemorySubjectRepository();
+        $this->now = new DateTimeImmutable('2026-03-15 10:00:00');
+
+        $this->seedClassesAndSubjects();
+    }
+
+    #[Test]
+    public function itReturnsReplacedClassesForTeacher(): void
+    {
+        $this->saveReplacement();
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertCount(1, $result);
+        self::assertContainsOnlyInstancesOf(ReplacedClassDto::class, $result);
+    }
+
+    #[Test]
+    public function itReturnsEmptyWhenNoReplacements(): void
+    {
+        $handler = $this->createHandler();
+        $result = $handler(new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itFlattensClassSubjectPairs(): void
+    {
+        $this->saveReplacementWithMultipleClasses();
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertCount(2, $result);
+
+        $classIds = array_map(static fn (ReplacedClassDto $dto) => $dto->classId, $result);
+        self::assertContains(self::CLASS_ID_1, $classIds);
+        self::assertContains(self::CLASS_ID_2, $classIds);
+
+        $subjectIds = array_map(static fn (ReplacedClassDto $dto) => $dto->subjectId, $result);
+        self::assertContains(self::SUBJECT_ID_1, $subjectIds);
+        self::assertContains(self::SUBJECT_ID_2, $subjectIds);
+    }
+
+    #[Test]
+    public function itOnlyReturnsActiveReplacements(): void
+    {
+        $replacement = $this->saveReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-10'));
+        $this->repository->save($replacement);
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itDoesNotReturnReplacementsForOtherTeachers(): void
+    {
+        $this->saveReplacement();
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: self::OTHER_TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itMapsDtoFieldsCorrectly(): void
+    {
+        $replacement = $this->saveReplacement();
+
+        $handler = $this->createHandler();
+        $result = $handler(new GetReplacedClassesForTeacherQuery(
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertCount(1, $result);
+
+        $dto = $result[0];
+        self::assertSame((string) $replacement->id, $dto->replacementId);
+        self::assertSame(self::REPLACED_TEACHER_ID, $dto->replacedTeacherId);
+        self::assertSame(self::CLASS_ID_1, $dto->classId);
+        self::assertSame(self::SUBJECT_ID_1, $dto->subjectId);
+        self::assertSame('6ème A', $dto->className);
+        self::assertSame('Mathématiques', $dto->subjectName);
+        self::assertEquals(new DateTimeImmutable('2026-03-01'), $dto->startDate);
+        self::assertEquals(new DateTimeImmutable('2026-03-31'), $dto->endDate);
+    }
+
+    private function saveReplacement(): TeacherReplacement
+    {
+        $replacement = TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID_1),
+                    SubjectId::fromString(self::SUBJECT_ID_1),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+
+        $this->repository->save($replacement);
+
+        return $replacement;
+    }
+
+    private function saveReplacementWithMultipleClasses(): TeacherReplacement
+    {
+        $replacement = TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID_1),
+                    SubjectId::fromString(self::SUBJECT_ID_1),
+                ),
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID_2),
+                    SubjectId::fromString(self::SUBJECT_ID_2),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+
+        $this->repository->save($replacement);
+
+        return $replacement;
+    }
+
+    private function seedClassesAndSubjects(): void
+    {
+        $tenantId = TenantId::fromString(self::TENANT_ID);
+        $schoolId = SchoolId::fromString(self::SCHOOL_ID);
+        $academicYearId = AcademicYearId::fromString(self::ACADEMIC_YEAR_ID);
+        $now = new DateTimeImmutable('2026-01-01');
+
+        $class1 = SchoolClass::reconstitute(
+            ClassId::fromString(self::CLASS_ID_1), $tenantId, $schoolId, $academicYearId,
+            new ClassName('6ème A'), null, null, ClassStatus::ACTIVE, null, $now, $now, null,
+        );
+        $this->classRepository->save($class1);
+
+        $class2 = SchoolClass::reconstitute(
+            ClassId::fromString(self::CLASS_ID_2), $tenantId, $schoolId, $academicYearId,
+            new ClassName('5ème B'), null, null, ClassStatus::ACTIVE, null, $now, $now, null,
+        );
+        $this->classRepository->save($class2);
+
+        $subject1 = Subject::reconstitute(
+            SubjectId::fromString(self::SUBJECT_ID_1), $tenantId, $schoolId,
+            new SubjectName('Mathématiques'), new SubjectCode('MATH'), null,
+            SubjectStatus::ACTIVE,
+            null, $now, $now, null,
+        );
+        $this->subjectRepository->save($subject1);
+
+        $subject2 = Subject::reconstitute(
+            SubjectId::fromString(self::SUBJECT_ID_2), $tenantId, $schoolId,
+            new SubjectName('Français'), new SubjectCode('FR'), null,
+            SubjectStatus::ACTIVE,
+            null, $now, $now, null,
+        );
+        $this->subjectRepository->save($subject2);
+    }
+
+    private function createHandler(): GetReplacedClassesForTeacherHandler
+    {
+        $now = $this->now;
+        $clock = new class($now) implements Clock {
+            public function __construct(private readonly DateTimeImmutable $now)
+            {
+            }
+
+            public function now(): DateTimeImmutable
+            {
+                return $this->now;
+            }
+        };
+
+        return new GetReplacedClassesForTeacherHandler(
+            $this->repository,
+            $this->classRepository,
+            $this->subjectRepository,
+            $clock,
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Application/Query/GetReplacedClassesForTeacher/ReplacedClassDtoTest.php b/backend/tests/Unit/Scolarite/Application/Query/GetReplacedClassesForTeacher/ReplacedClassDtoTest.php
new file mode 100644
index 0000000..2c079e3
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Application/Query/GetReplacedClassesForTeacher/ReplacedClassDtoTest.php
@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Query\GetReplacedClassesForTeacher;
+
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\ReplacedClassDto;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class ReplacedClassDtoTest extends TestCase
+{
+    private const string REPLACEMENT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+
+    #[Test]
+    public function constructorSetsAllPropertiesCorrectly(): void
+    {
+        $startDate = new DateTimeImmutable('2026-03-01');
+        $endDate = new DateTimeImmutable('2026-03-31');
+
+        $dto = new ReplacedClassDto(
+            replacementId: self::REPLACEMENT_ID,
+            replacedTeacherId: self::REPLACED_TEACHER_ID,
+            classId: self::CLASS_ID,
+            subjectId: self::SUBJECT_ID,
+            className: '6ème A',
+            subjectName: 'Mathématiques',
+            startDate: $startDate,
+            endDate: $endDate,
+        );
+
+        self::assertSame(self::REPLACEMENT_ID, $dto->replacementId);
+        self::assertSame(self::REPLACED_TEACHER_ID, $dto->replacedTeacherId);
+        self::assertSame(self::CLASS_ID, $dto->classId);
+        self::assertSame(self::SUBJECT_ID, $dto->subjectId);
+        self::assertSame('6ème A', $dto->className);
+        self::assertSame('Mathématiques', $dto->subjectName);
+        self::assertEquals($startDate, $dto->startDate);
+        self::assertEquals($endDate, $dto->endDate);
+    }
+
+    #[Test]
+    public function constructorPreservesExactDateValues(): void
+    {
+        $startDate = new DateTimeImmutable('2026-03-01 08:00:00');
+        $endDate = new DateTimeImmutable('2026-03-31 23:59:59');
+
+        $dto = new ReplacedClassDto(
+            replacementId: self::REPLACEMENT_ID,
+            replacedTeacherId: self::REPLACED_TEACHER_ID,
+            classId: self::CLASS_ID,
+            subjectId: self::SUBJECT_ID,
+            className: '6ème A',
+            subjectName: 'Mathématiques',
+            startDate: $startDate,
+            endDate: $endDate,
+        );
+
+        self::assertSame($startDate, $dto->startDate);
+        self::assertSame($endDate, $dto->endDate);
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacementTest.php b/backend/tests/Unit/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacementTest.php
new file mode 100644
index 0000000..68ab674
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Domain/Model/TeacherReplacement/TeacherReplacementTest.php
@@ -0,0 +1,331 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Domain\Model\TeacherReplacement;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Event\RemplacementDesigne;
+use App\Scolarite\Domain\Event\RemplacementTermine;
+use App\Scolarite\Domain\Exception\DatesRemplacementInvalidesException;
+use App\Scolarite\Domain\Exception\RemplacementDejaTermineException;
+use App\Scolarite\Domain\Exception\RemplacementSameTeacherException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class TeacherReplacementTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    #[Test]
+    public function designerCreatesActiveReplacement(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertSame(ReplacementStatus::ACTIVE, $replacement->status);
+        self::assertNull($replacement->endedAt);
+    }
+
+    #[Test]
+    public function designerRecordsRemplacementDesigneEvent(): void
+    {
+        $replacement = $this->createReplacement();
+
+        $events = $replacement->pullDomainEvents();
+
+        self::assertCount(1, $events);
+        self::assertInstanceOf(RemplacementDesigne::class, $events[0]);
+        self::assertSame($replacement->id, $events[0]->replacementId);
+        self::assertTrue($replacement->replacedTeacherId->equals($events[0]->replacedTeacherId));
+        self::assertTrue($replacement->replacementTeacherId->equals($events[0]->replacementTeacherId));
+    }
+
+    #[Test]
+    public function designerSetsAllProperties(): void
+    {
+        $tenantId = TenantId::fromString(self::TENANT_ID);
+        $replacedTeacherId = UserId::fromString(self::REPLACED_TEACHER_ID);
+        $replacementTeacherId = UserId::fromString(self::REPLACEMENT_TEACHER_ID);
+        $startDate = new DateTimeImmutable('2026-03-01');
+        $endDate = new DateTimeImmutable('2026-03-31');
+        $classes = $this->createClasses();
+        $createdBy = UserId::fromString(self::CREATED_BY_ID);
+        $now = new DateTimeImmutable('2026-02-15 10:00:00');
+
+        $replacement = TeacherReplacement::designer(
+            tenantId: $tenantId,
+            replacedTeacherId: $replacedTeacherId,
+            replacementTeacherId: $replacementTeacherId,
+            startDate: $startDate,
+            endDate: $endDate,
+            classes: $classes,
+            reason: 'Congé maladie',
+            createdBy: $createdBy,
+            now: $now,
+        );
+
+        self::assertTrue($replacement->tenantId->equals($tenantId));
+        self::assertTrue($replacement->replacedTeacherId->equals($replacedTeacherId));
+        self::assertTrue($replacement->replacementTeacherId->equals($replacementTeacherId));
+        self::assertEquals($startDate, $replacement->startDate);
+        self::assertEquals($endDate, $replacement->endDate);
+        self::assertCount(1, $replacement->classes);
+        self::assertSame('Congé maladie', $replacement->reason);
+        self::assertTrue($replacement->createdBy->equals($createdBy));
+        self::assertEquals($now, $replacement->createdAt);
+        self::assertEquals($now, $replacement->updatedAt);
+        self::assertNull($replacement->endedAt);
+    }
+
+    #[Test]
+    public function designerThrowsWhenSameTeacher(): void
+    {
+        $this->expectException(RemplacementSameTeacherException::class);
+
+        $sameTeacherId = UserId::fromString(self::REPLACED_TEACHER_ID);
+
+        TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: $sameTeacherId,
+            replacementTeacherId: $sameTeacherId,
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: $this->createClasses(),
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+
+    #[Test]
+    public function designerThrowsWhenEndDateBeforeStartDate(): void
+    {
+        $this->expectException(DatesRemplacementInvalidesException::class);
+
+        TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-31'),
+            endDate: new DateTimeImmutable('2026-03-01'),
+            classes: $this->createClasses(),
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+
+    #[Test]
+    public function isActiveReturnsTrueWhenWithinDateRange(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertTrue($replacement->isActive(new DateTimeImmutable('2026-03-15')));
+    }
+
+    #[Test]
+    public function isActiveReturnsTrueOnStartDate(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertTrue($replacement->isActive(new DateTimeImmutable('2026-03-01')));
+    }
+
+    #[Test]
+    public function isActiveReturnsTrueOnEndDate(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertTrue($replacement->isActive(new DateTimeImmutable('2026-03-31')));
+    }
+
+    #[Test]
+    public function isActiveReturnsFalseBeforeStartDate(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertFalse($replacement->isActive(new DateTimeImmutable('2026-02-28')));
+    }
+
+    #[Test]
+    public function isActiveReturnsFalseAfterEndDate(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertFalse($replacement->isActive(new DateTimeImmutable('2026-04-01')));
+    }
+
+    #[Test]
+    public function isActiveReturnsFalseWhenEnded(): void
+    {
+        $replacement = $this->createReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-15'));
+
+        self::assertFalse($replacement->isActive(new DateTimeImmutable('2026-03-15')));
+    }
+
+    #[Test]
+    public function isExpiredReturnsTrueAfterEndDate(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertTrue($replacement->isExpired(new DateTimeImmutable('2026-04-01')));
+    }
+
+    #[Test]
+    public function isExpiredReturnsFalseWhenStillActive(): void
+    {
+        $replacement = $this->createReplacement();
+
+        self::assertFalse($replacement->isExpired(new DateTimeImmutable('2026-03-15')));
+    }
+
+    #[Test]
+    public function isExpiredReturnsFalseWhenAlreadyEnded(): void
+    {
+        $replacement = $this->createReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-15'));
+
+        self::assertFalse($replacement->isExpired(new DateTimeImmutable('2026-04-01')));
+    }
+
+    #[Test]
+    public function terminerChangesStatusAndRecordsEvent(): void
+    {
+        $replacement = $this->createReplacement();
+        $replacement->pullDomainEvents();
+        $at = new DateTimeImmutable('2026-03-15 14:00:00');
+
+        $replacement->terminer($at);
+
+        self::assertSame(ReplacementStatus::ENDED, $replacement->status);
+        self::assertEquals($at, $replacement->endedAt);
+        self::assertEquals($at, $replacement->updatedAt);
+
+        $events = $replacement->pullDomainEvents();
+        self::assertCount(1, $events);
+        self::assertInstanceOf(RemplacementTermine::class, $events[0]);
+        self::assertSame($replacement->id, $events[0]->replacementId);
+    }
+
+    #[Test]
+    public function terminerThrowsWhenAlreadyEnded(): void
+    {
+        $replacement = $this->createReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-15'));
+
+        $this->expectException(RemplacementDejaTermineException::class);
+
+        $replacement->terminer(new DateTimeImmutable('2026-03-16'));
+    }
+
+    #[Test]
+    public function couvreClasseMatiereReturnsTrueForMatchingPair(): void
+    {
+        $replacement = $this->createReplacement();
+        $pair = new ClassSubjectPair(
+            ClassId::fromString(self::CLASS_ID),
+            SubjectId::fromString(self::SUBJECT_ID),
+        );
+
+        self::assertTrue($replacement->couvreClasseMatiere($pair));
+    }
+
+    #[Test]
+    public function couvreClasseMatiereReturnsFalseForNonMatchingPair(): void
+    {
+        $replacement = $this->createReplacement();
+        $pair = new ClassSubjectPair(
+            ClassId::fromString('550e8400-e29b-41d4-a716-446655440099'),
+            SubjectId::fromString(self::SUBJECT_ID),
+        );
+
+        self::assertFalse($replacement->couvreClasseMatiere($pair));
+    }
+
+    #[Test]
+    public function reconstituteRestoresAllPropertiesWithoutEvents(): void
+    {
+        $id = TeacherReplacementId::generate();
+        $tenantId = TenantId::fromString(self::TENANT_ID);
+        $replacedTeacherId = UserId::fromString(self::REPLACED_TEACHER_ID);
+        $replacementTeacherId = UserId::fromString(self::REPLACEMENT_TEACHER_ID);
+        $startDate = new DateTimeImmutable('2026-03-01');
+        $endDate = new DateTimeImmutable('2026-03-31');
+        $classes = $this->createClasses();
+        $createdBy = UserId::fromString(self::CREATED_BY_ID);
+        $createdAt = new DateTimeImmutable('2026-02-15 10:00:00');
+        $endedAt = new DateTimeImmutable('2026-03-20 10:00:00');
+        $updatedAt = new DateTimeImmutable('2026-03-20 10:00:00');
+
+        $replacement = TeacherReplacement::reconstitute(
+            id: $id,
+            tenantId: $tenantId,
+            replacedTeacherId: $replacedTeacherId,
+            replacementTeacherId: $replacementTeacherId,
+            startDate: $startDate,
+            endDate: $endDate,
+            status: ReplacementStatus::ENDED,
+            classes: $classes,
+            reason: 'Congé maladie',
+            createdBy: $createdBy,
+            createdAt: $createdAt,
+            endedAt: $endedAt,
+            updatedAt: $updatedAt,
+        );
+
+        self::assertTrue($replacement->id->equals($id));
+        self::assertTrue($replacement->tenantId->equals($tenantId));
+        self::assertTrue($replacement->replacedTeacherId->equals($replacedTeacherId));
+        self::assertTrue($replacement->replacementTeacherId->equals($replacementTeacherId));
+        self::assertEquals($startDate, $replacement->startDate);
+        self::assertEquals($endDate, $replacement->endDate);
+        self::assertSame(ReplacementStatus::ENDED, $replacement->status);
+        self::assertCount(1, $replacement->classes);
+        self::assertSame('Congé maladie', $replacement->reason);
+        self::assertTrue($replacement->createdBy->equals($createdBy));
+        self::assertEquals($createdAt, $replacement->createdAt);
+        self::assertEquals($endedAt, $replacement->endedAt);
+        self::assertEquals($updatedAt, $replacement->updatedAt);
+        self::assertEmpty($replacement->pullDomainEvents());
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: $this->createClasses(),
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+
+    /** @return array<ClassSubjectPair> */
+    private function createClasses(): array
+    {
+        return [
+            new ClassSubjectPair(
+                ClassId::fromString(self::CLASS_ID),
+                SubjectId::fromString(self::SUBJECT_ID),
+            ),
+        ];
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Api/Processor/CreateTeacherReplacementProcessorTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Api/Processor/CreateTeacherReplacementProcessorTest.php
new file mode 100644
index 0000000..c5c91ce
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Api/Processor/CreateTeacherReplacementProcessorTest.php
@@ -0,0 +1,324 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Api\Processor;
+
+use ApiPlatform\Metadata\Post;
+use App\Administration\Domain\Model\User\Email;
+use App\Administration\Domain\Model\User\Role;
+use App\Administration\Domain\Model\User\StatutCompte;
+use App\Administration\Domain\Model\User\User;
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemoryUserRepository;
+use App\Administration\Infrastructure\Security\SecurityUser;
+use App\Scolarite\Application\Command\DesignateReplacement\DesignateReplacementHandler;
+use App\Scolarite\Infrastructure\Api\Processor\CreateTeacherReplacementProcessor;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use App\Shared\Infrastructure\Tenant\TenantConfig;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use App\Shared\Infrastructure\Tenant\TenantId as InfraTenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Bundle\SecurityBundle\Security;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Security\Core\Authorization\AccessDecision;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+final class CreateTeacherReplacementProcessorTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string ADMIN_USER_ID = '550e8400-e29b-41d4-a716-446655440099';
+    private const string OTHER_TENANT_ID = '550e8400-e29b-41d4-a716-446655440002';
+    private const string OTHER_TENANT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440012';
+    private const string NON_TEACHER_USER_ID = '550e8400-e29b-41d4-a716-446655440050';
+
+    private InMemoryTeacherReplacementRepository $replacementRepository;
+    private InMemoryUserRepository $userRepository;
+    private TenantContext $tenantContext;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->replacementRepository = new InMemoryTeacherReplacementRepository();
+        $this->userRepository = new InMemoryUserRepository();
+        $this->tenantContext = new TenantContext();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-02-15 10:00:00');
+            }
+        };
+
+        $this->seedTestData();
+    }
+
+    #[Test]
+    public function itCreatesReplacementSuccessfully(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+
+        $result = $processor->process($data, new Post());
+
+        self::assertInstanceOf(TeacherReplacementResource::class, $result);
+        self::assertNotNull($result->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $result->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $result->replacementTeacherId);
+        self::assertSame('2026-03-01', $result->startDate);
+        self::assertSame('2026-03-31', $result->endDate);
+        self::assertSame('active', $result->status);
+        self::assertSame('Congé maladie', $result->reason);
+        self::assertCount(1, $result->classes);
+    }
+
+    #[Test]
+    public function itRejectsUnauthorizedAccess(): void
+    {
+        $processor = $this->createProcessor(granted: false);
+        $this->setTenant();
+
+        $this->expectException(AccessDeniedHttpException::class);
+        $processor->process($this->createResource(), new Post());
+    }
+
+    #[Test]
+    public function itRejectsRequestWithoutTenant(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+
+        $this->expectException(UnauthorizedHttpException::class);
+        $processor->process($this->createResource(), new Post());
+    }
+
+    #[Test]
+    public function itMapsSameTeacherExceptionToBadRequest(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+        $data->replacementTeacherId = self::REPLACED_TEACHER_ID;
+
+        $this->expectException(BadRequestHttpException::class);
+        $processor->process($data, new Post());
+    }
+
+    #[Test]
+    public function itMapsInvalidDatesExceptionToBadRequest(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+        $data->startDate = '2026-03-31';
+        $data->endDate = '2026-03-01';
+
+        $this->expectException(BadRequestHttpException::class);
+        $processor->process($data, new Post());
+    }
+
+    #[Test]
+    public function itMapsUserNotFoundExceptionToNotFound(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+        $data->replacedTeacherId = '550e8400-e29b-41d4-a716-446655440088';
+
+        $this->expectException(NotFoundHttpException::class);
+        $processor->process($data, new Post());
+    }
+
+    #[Test]
+    public function itMapsInvalidUuidToBadRequest(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+        $data->replacedTeacherId = 'not-a-valid-uuid';
+
+        $this->expectException(BadRequestHttpException::class);
+        $processor->process($data, new Post());
+    }
+
+    #[Test]
+    public function itMapsTenantMismatchExceptionToBadRequest(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+        $data->replacedTeacherId = self::OTHER_TENANT_TEACHER_ID;
+
+        $this->expectException(BadRequestHttpException::class);
+        $processor->process($data, new Post());
+    }
+
+    #[Test]
+    public function itMapsNonTeacherExceptionToBadRequest(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $data = $this->createResource();
+        $data->replacedTeacherId = self::NON_TEACHER_USER_ID;
+
+        $this->expectException(BadRequestHttpException::class);
+        $processor->process($data, new Post());
+    }
+
+    private function seedTestData(): void
+    {
+        $tenantId = TenantId::fromString(self::TENANT_ID);
+
+        $replacedTeacher = User::reconstitute(
+            id: UserId::fromString(self::REPLACED_TEACHER_ID),
+            email: new Email('replaced@example.com'),
+            roles: [Role::PROF],
+            tenantId: $tenantId,
+            schoolName: 'École Test',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($replacedTeacher);
+
+        $replacementTeacher = User::reconstitute(
+            id: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            email: new Email('replacement@example.com'),
+            roles: [Role::PROF],
+            tenantId: $tenantId,
+            schoolName: 'École Test',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($replacementTeacher);
+
+        // Enseignant d'un autre tenant
+        $otherTenantTeacher = User::reconstitute(
+            id: UserId::fromString(self::OTHER_TENANT_TEACHER_ID),
+            email: new Email('other-tenant@example.com'),
+            roles: [Role::PROF],
+            tenantId: TenantId::fromString(self::OTHER_TENANT_ID),
+            schoolName: 'Autre École',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($otherTenantTeacher);
+
+        // Utilisateur non-enseignant dans le même tenant
+        $nonTeacherUser = User::reconstitute(
+            id: UserId::fromString(self::NON_TEACHER_USER_ID),
+            email: new Email('admin-user@example.com'),
+            roles: [Role::ADMIN],
+            tenantId: $tenantId,
+            schoolName: 'École Test',
+            statut: StatutCompte::EN_ATTENTE,
+            dateNaissance: null,
+            createdAt: new DateTimeImmutable('2026-01-15'),
+            hashedPassword: null,
+            activatedAt: null,
+            consentementParental: null,
+        );
+        $this->userRepository->save($nonTeacherUser);
+    }
+
+    private function setTenant(): void
+    {
+        $this->tenantContext->setCurrentTenant(new TenantConfig(
+            tenantId: InfraTenantId::fromString(self::TENANT_ID),
+            subdomain: 'test',
+            databaseUrl: 'sqlite:///:memory:',
+        ));
+    }
+
+    private function createResource(): TeacherReplacementResource
+    {
+        $data = new TeacherReplacementResource();
+        $data->replacedTeacherId = self::REPLACED_TEACHER_ID;
+        $data->replacementTeacherId = self::REPLACEMENT_TEACHER_ID;
+        $data->startDate = '2026-03-01';
+        $data->endDate = '2026-03-31';
+        $data->classes = [
+            ['classId' => self::CLASS_ID, 'subjectId' => self::SUBJECT_ID],
+        ];
+        $data->reason = 'Congé maladie';
+
+        return $data;
+    }
+
+    private function createProcessor(bool $granted): CreateTeacherReplacementProcessor
+    {
+        $authChecker = new class($granted) implements AuthorizationCheckerInterface {
+            public function __construct(private readonly bool $granted)
+            {
+            }
+
+            public function isGranted(mixed $attribute, mixed $subject = null, ?AccessDecision $accessDecision = null): bool
+            {
+                return $this->granted;
+            }
+        };
+
+        $eventBus = new class implements MessageBusInterface {
+            public function dispatch(object $message, array $stamps = []): Envelope
+            {
+                return new Envelope($message);
+            }
+        };
+
+        $handler = new DesignateReplacementHandler(
+            $this->replacementRepository,
+            $this->userRepository,
+            $this->clock,
+        );
+
+        $securityUser = new SecurityUser(
+            UserId::fromString(self::ADMIN_USER_ID),
+            'admin@example.com',
+            'hashed',
+            TenantId::fromString(self::TENANT_ID),
+            [Role::ADMIN->value],
+        );
+
+        $security = $this->createStub(Security::class);
+        $security->method('getUser')->willReturn($securityUser);
+
+        return new CreateTeacherReplacementProcessor(
+            $handler,
+            $this->tenantContext,
+            $eventBus,
+            $authChecker,
+            $security,
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Api/Processor/EndTeacherReplacementProcessorTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Api/Processor/EndTeacherReplacementProcessorTest.php
new file mode 100644
index 0000000..0402094
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Api/Processor/EndTeacherReplacementProcessorTest.php
@@ -0,0 +1,196 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Api\Processor;
+
+use ApiPlatform\Metadata\Delete;
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementHandler;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Api\Processor\EndTeacherReplacementProcessor;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use App\Shared\Infrastructure\Tenant\TenantConfig;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use App\Shared\Infrastructure\Tenant\TenantId as InfraTenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Security\Core\Authorization\AccessDecision;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+final class EndTeacherReplacementProcessorTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $replacementRepository;
+    private TenantContext $tenantContext;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->replacementRepository = new InMemoryTeacherReplacementRepository();
+        $this->tenantContext = new TenantContext();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-03-15 10:00:00');
+            }
+        };
+    }
+
+    #[Test]
+    public function itEndsReplacementSuccessfully(): void
+    {
+        $replacement = $this->createAndSaveReplacement();
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $result = $processor->process(
+            new TeacherReplacementResource(),
+            new Delete(),
+            ['id' => (string) $replacement->id],
+        );
+
+        self::assertNull($result);
+
+        $ended = $this->replacementRepository->get($replacement->id, TenantId::fromString(self::TENANT_ID));
+        self::assertSame(ReplacementStatus::ENDED, $ended->status);
+        self::assertNotNull($ended->endedAt);
+    }
+
+    #[Test]
+    public function itRejectsUnauthorizedAccess(): void
+    {
+        $replacement = $this->createAndSaveReplacement();
+        $processor = $this->createProcessor(granted: false);
+        $this->setTenant();
+
+        $this->expectException(AccessDeniedHttpException::class);
+        $processor->process(
+            new TeacherReplacementResource(),
+            new Delete(),
+            ['id' => (string) $replacement->id],
+        );
+    }
+
+    #[Test]
+    public function itRejectsRequestWithoutTenant(): void
+    {
+        $replacement = $this->createAndSaveReplacement();
+        $processor = $this->createProcessor(granted: true);
+
+        $this->expectException(UnauthorizedHttpException::class);
+        $processor->process(
+            new TeacherReplacementResource(),
+            new Delete(),
+            ['id' => (string) $replacement->id],
+        );
+    }
+
+    #[Test]
+    public function itMapsNotFoundExceptionToHttpNotFound(): void
+    {
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $this->expectException(NotFoundHttpException::class);
+        $processor->process(
+            new TeacherReplacementResource(),
+            new Delete(),
+            ['id' => '550e8400-e29b-41d4-a716-446655440088'],
+        );
+    }
+
+    #[Test]
+    public function itMapsAlreadyEndedExceptionToBadRequest(): void
+    {
+        $replacement = $this->createAndSaveReplacement();
+        $replacement->terminer(new DateTimeImmutable('2026-03-10'));
+        $this->replacementRepository->save($replacement);
+
+        $processor = $this->createProcessor(granted: true);
+        $this->setTenant();
+
+        $this->expectException(BadRequestHttpException::class);
+        $processor->process(
+            new TeacherReplacementResource(),
+            new Delete(),
+            ['id' => (string) $replacement->id],
+        );
+    }
+
+    private function createAndSaveReplacement(): TeacherReplacement
+    {
+        $replacement = TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+
+        $this->replacementRepository->save($replacement);
+
+        return $replacement;
+    }
+
+    private function setTenant(): void
+    {
+        $this->tenantContext->setCurrentTenant(new TenantConfig(
+            tenantId: InfraTenantId::fromString(self::TENANT_ID),
+            subdomain: 'test',
+            databaseUrl: 'sqlite:///:memory:',
+        ));
+    }
+
+    private function createProcessor(bool $granted): EndTeacherReplacementProcessor
+    {
+        $authChecker = new class($granted) implements AuthorizationCheckerInterface {
+            public function __construct(private readonly bool $granted)
+            {
+            }
+
+            public function isGranted(mixed $attribute, mixed $subject = null, ?AccessDecision $accessDecision = null): bool
+            {
+                return $this->granted;
+            }
+        };
+
+        $handler = new EndReplacementHandler(
+            $this->replacementRepository,
+            $this->clock,
+        );
+
+        return new EndTeacherReplacementProcessor(
+            $handler,
+            $this->tenantContext,
+            $authChecker,
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/ReplacedClassesProviderTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/ReplacedClassesProviderTest.php
new file mode 100644
index 0000000..3a2d169
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/ReplacedClassesProviderTest.php
@@ -0,0 +1,208 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Api\Provider;
+
+use ApiPlatform\Metadata\GetCollection;
+use App\Administration\Domain\Model\SchoolClass\AcademicYearId;
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\SchoolClass\ClassName;
+use App\Administration\Domain\Model\SchoolClass\ClassStatus;
+use App\Administration\Domain\Model\SchoolClass\SchoolClass;
+use App\Administration\Domain\Model\SchoolClass\SchoolId;
+use App\Administration\Domain\Model\Subject\Subject;
+use App\Administration\Domain\Model\Subject\SubjectCode;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\Subject\SubjectName;
+use App\Administration\Domain\Model\Subject\SubjectStatus;
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemoryClassRepository;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemorySubjectRepository;
+use App\Administration\Infrastructure\Security\SecurityUser;
+use App\Scolarite\Application\Query\GetReplacedClassesForTeacher\GetReplacedClassesForTeacherHandler;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Api\Provider\ReplacedClassesProvider;
+use App\Scolarite\Infrastructure\Api\Resource\ReplacedClassResource;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use App\Shared\Infrastructure\Tenant\TenantConfig;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use App\Shared\Infrastructure\Tenant\TenantId as InfraTenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Bundle\SecurityBundle\Security;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+
+final class ReplacedClassesProviderTest extends TestCase
+{
+    private const string TENANT_UUID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+    private const string SCHOOL_ID = '550e8400-e29b-41d4-a716-446655440040';
+    private const string ACADEMIC_YEAR_ID = '550e8400-e29b-41d4-a716-446655440041';
+
+    private InMemoryTeacherReplacementRepository $repository;
+    private InMemoryClassRepository $classRepository;
+    private InMemorySubjectRepository $subjectRepository;
+    private TenantContext $tenantContext;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+        $this->classRepository = new InMemoryClassRepository();
+        $this->subjectRepository = new InMemorySubjectRepository();
+        $this->tenantContext = new TenantContext();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-03-15 10:00:00');
+            }
+        };
+
+        $this->seedClassesAndSubjects();
+    }
+
+    #[Test]
+    public function itProvidesReplacedClassesForAuthenticatedTeacher(): void
+    {
+        $provider = $this->createProvider(self::REPLACEMENT_TEACHER_ID);
+        $this->setTenant();
+
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $provider->provide(new GetCollection());
+
+        self::assertCount(1, $result);
+        self::assertContainsOnlyInstancesOf(ReplacedClassResource::class, $result);
+        self::assertSame((string) $replacement->id, $result[0]->replacementId);
+        self::assertSame(self::REPLACED_TEACHER_ID, $result[0]->replacedTeacherId);
+        self::assertSame(self::CLASS_ID, $result[0]->classId);
+        self::assertSame(self::SUBJECT_ID, $result[0]->subjectId);
+    }
+
+    #[Test]
+    public function itReturnsEmptyWhenNoReplacements(): void
+    {
+        $provider = $this->createProvider(self::REPLACEMENT_TEACHER_ID);
+        $this->setTenant();
+
+        $result = $provider->provide(new GetCollection());
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itThrowsWhenUserNotAuthenticated(): void
+    {
+        $security = $this->createMock(Security::class);
+        $security->method('getUser')->willReturn(null);
+
+        $handler = new GetReplacedClassesForTeacherHandler(
+            $this->repository,
+            $this->classRepository,
+            $this->subjectRepository,
+            $this->clock,
+        );
+
+        $provider = new ReplacedClassesProvider($handler, $this->tenantContext, $security);
+        $this->setTenant();
+
+        $this->expectException(UnauthorizedHttpException::class);
+        $this->expectExceptionMessage('Authentification requise.');
+        $provider->provide(new GetCollection());
+    }
+
+    #[Test]
+    public function itThrowsWhenTenantNotSet(): void
+    {
+        $provider = $this->createProvider(self::REPLACEMENT_TEACHER_ID);
+
+        $this->expectException(UnauthorizedHttpException::class);
+        $this->expectExceptionMessage('Tenant non défini.');
+        $provider->provide(new GetCollection());
+    }
+
+    private function setTenant(): void
+    {
+        $this->tenantContext->setCurrentTenant(new TenantConfig(
+            tenantId: InfraTenantId::fromString(self::TENANT_UUID),
+            subdomain: 'test',
+            databaseUrl: 'sqlite:///:memory:',
+        ));
+    }
+
+    private function createProvider(string $userId): ReplacedClassesProvider
+    {
+        $securityUser = new SecurityUser(
+            UserId::fromString($userId),
+            'teacher@test.com',
+            'hashed',
+            TenantId::fromString(self::TENANT_UUID),
+            ['ROLE_PROF'],
+        );
+
+        $security = $this->createMock(Security::class);
+        $security->method('getUser')->willReturn($securityUser);
+
+        $handler = new GetReplacedClassesForTeacherHandler(
+            $this->repository,
+            $this->classRepository,
+            $this->subjectRepository,
+            $this->clock,
+        );
+
+        return new ReplacedClassesProvider($handler, $this->tenantContext, $security);
+    }
+
+    private function seedClassesAndSubjects(): void
+    {
+        $tenantId = TenantId::fromString(self::TENANT_UUID);
+        $schoolId = SchoolId::fromString(self::SCHOOL_ID);
+        $academicYearId = AcademicYearId::fromString(self::ACADEMIC_YEAR_ID);
+        $now = new DateTimeImmutable('2026-01-01');
+
+        $class = SchoolClass::reconstitute(
+            ClassId::fromString(self::CLASS_ID), $tenantId, $schoolId, $academicYearId,
+            new ClassName('6ème A'), null, null,
+            ClassStatus::ACTIVE,
+            null, $now, $now, null,
+        );
+        $this->classRepository->save($class);
+
+        $subject = Subject::reconstitute(
+            SubjectId::fromString(self::SUBJECT_ID), $tenantId, $schoolId,
+            new SubjectName('Mathématiques'), new SubjectCode('MATH'), null,
+            SubjectStatus::ACTIVE, null, $now, $now, null,
+        );
+        $this->subjectRepository->save($subject);
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_UUID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/TeacherReplacementItemProviderTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/TeacherReplacementItemProviderTest.php
new file mode 100644
index 0000000..9c0e88d
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/TeacherReplacementItemProviderTest.php
@@ -0,0 +1,154 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Api\Provider;
+
+use ApiPlatform\Metadata\Delete;
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Api\Provider\TeacherReplacementItemProvider;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Tenant\TenantId;
+use App\Shared\Infrastructure\Tenant\TenantConfig;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use App\Shared\Infrastructure\Tenant\TenantId as InfraTenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Security\Core\Authorization\AccessDecision;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+final class TeacherReplacementItemProviderTest extends TestCase
+{
+    private const string TENANT_UUID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $repository;
+    private TenantContext $tenantContext;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+        $this->tenantContext = new TenantContext();
+    }
+
+    #[Test]
+    public function itProvidesSingleReplacementById(): void
+    {
+        $provider = $this->createProvider(granted: true);
+        $this->setTenant();
+
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $provider->provide(
+            new Delete(),
+            ['id' => (string) $replacement->id],
+        );
+
+        self::assertInstanceOf(TeacherReplacementResource::class, $result);
+        self::assertSame((string) $replacement->id, $result->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $result->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $result->replacementTeacherId);
+        self::assertSame('active', $result->status);
+    }
+
+    #[Test]
+    public function itThrowsNotFoundWhenReplacementDoesNotExist(): void
+    {
+        $provider = $this->createProvider(granted: true);
+        $this->setTenant();
+
+        $this->expectException(NotFoundHttpException::class);
+        $this->expectExceptionMessage('Remplacement non trouvé.');
+
+        $provider->provide(
+            new Delete(),
+            ['id' => '550e8400-e29b-41d4-a716-446655440099'],
+        );
+    }
+
+    #[Test]
+    public function itRejectsUnauthorizedAccess(): void
+    {
+        $provider = $this->createProvider(granted: false);
+        $this->setTenant();
+
+        $this->expectException(AccessDeniedHttpException::class);
+
+        $provider->provide(
+            new Delete(),
+            ['id' => '550e8400-e29b-41d4-a716-446655440099'],
+        );
+    }
+
+    #[Test]
+    public function itRejectsRequestWithoutTenant(): void
+    {
+        $provider = $this->createProvider(granted: true);
+
+        $this->expectException(UnauthorizedHttpException::class);
+
+        $provider->provide(
+            new Delete(),
+            ['id' => '550e8400-e29b-41d4-a716-446655440099'],
+        );
+    }
+
+    private function setTenant(): void
+    {
+        $this->tenantContext->setCurrentTenant(new TenantConfig(
+            tenantId: InfraTenantId::fromString(self::TENANT_UUID),
+            subdomain: 'test',
+            databaseUrl: 'sqlite:///:memory:',
+        ));
+    }
+
+    private function createProvider(bool $granted): TeacherReplacementItemProvider
+    {
+        $authChecker = new class($granted) implements AuthorizationCheckerInterface {
+            public function __construct(private readonly bool $granted)
+            {
+            }
+
+            public function isGranted(mixed $attribute, mixed $subject = null, ?AccessDecision $accessDecision = null): bool
+            {
+                return $this->granted;
+            }
+        };
+
+        return new TeacherReplacementItemProvider($this->repository, $this->tenantContext, $authChecker);
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_UUID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/TeacherReplacementsCollectionProviderTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/TeacherReplacementsCollectionProviderTest.php
new file mode 100644
index 0000000..a178d70
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Api/Provider/TeacherReplacementsCollectionProviderTest.php
@@ -0,0 +1,150 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Api\Provider;
+
+use ApiPlatform\Metadata\GetCollection;
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Query\GetActiveReplacements\GetActiveReplacementsHandler;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Api\Provider\TeacherReplacementsCollectionProvider;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use App\Shared\Infrastructure\Tenant\TenantConfig;
+use App\Shared\Infrastructure\Tenant\TenantContext;
+use App\Shared\Infrastructure\Tenant\TenantId as InfraTenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
+use Symfony\Component\Security\Core\Authorization\AccessDecision;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+
+final class TeacherReplacementsCollectionProviderTest extends TestCase
+{
+    private const string TENANT_UUID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $repository;
+    private TenantContext $tenantContext;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+        $this->tenantContext = new TenantContext();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-03-15 10:00:00');
+            }
+        };
+    }
+
+    #[Test]
+    public function itProvidesCollectionOfActiveReplacements(): void
+    {
+        $provider = $this->createProvider(granted: true);
+        $this->setTenant();
+
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $provider->provide(new GetCollection());
+
+        self::assertCount(1, $result);
+        self::assertContainsOnlyInstancesOf(TeacherReplacementResource::class, $result);
+        self::assertSame((string) $replacement->id, $result[0]->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $result[0]->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $result[0]->replacementTeacherId);
+        self::assertSame('active', $result[0]->status);
+    }
+
+    #[Test]
+    public function itReturnsEmptyWhenNoActiveReplacements(): void
+    {
+        $provider = $this->createProvider(granted: true);
+        $this->setTenant();
+
+        $result = $provider->provide(new GetCollection());
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itRejectsUnauthorizedAccess(): void
+    {
+        $provider = $this->createProvider(granted: false);
+        $this->setTenant();
+
+        $this->expectException(AccessDeniedHttpException::class);
+        $provider->provide(new GetCollection());
+    }
+
+    #[Test]
+    public function itRejectsRequestWithoutTenant(): void
+    {
+        $provider = $this->createProvider(granted: true);
+
+        $this->expectException(UnauthorizedHttpException::class);
+        $provider->provide(new GetCollection());
+    }
+
+    private function setTenant(): void
+    {
+        $this->tenantContext->setCurrentTenant(new TenantConfig(
+            tenantId: InfraTenantId::fromString(self::TENANT_UUID),
+            subdomain: 'test',
+            databaseUrl: 'sqlite:///:memory:',
+        ));
+    }
+
+    private function createProvider(bool $granted): TeacherReplacementsCollectionProvider
+    {
+        $authChecker = new class($granted) implements AuthorizationCheckerInterface {
+            public function __construct(private readonly bool $granted)
+            {
+            }
+
+            public function isGranted(mixed $attribute, mixed $subject = null, ?AccessDecision $accessDecision = null): bool
+            {
+                return $this->granted;
+            }
+        };
+
+        $handler = new GetActiveReplacementsHandler($this->repository, $this->clock);
+
+        return new TeacherReplacementsCollectionProvider($handler, $this->tenantContext, $authChecker);
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_UUID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: 'Congé maladie',
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Api/Resource/TeacherReplacementResourceTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Api/Resource/TeacherReplacementResourceTest.php
new file mode 100644
index 0000000..7fbd531
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Api/Resource/TeacherReplacementResourceTest.php
@@ -0,0 +1,143 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Api\Resource;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Query\GetActiveReplacements\ReplacementDto;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Api\Resource\TeacherReplacementResource;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class TeacherReplacementResourceTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    #[Test]
+    public function fromDomainCreatesCorrectResource(): void
+    {
+        $replacement = $this->createReplacement();
+
+        $resource = TeacherReplacementResource::fromDomain($replacement);
+
+        self::assertSame((string) $replacement->id, $resource->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $resource->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $resource->replacementTeacherId);
+        self::assertSame('2026-03-01', $resource->startDate);
+        self::assertSame('2026-03-31', $resource->endDate);
+        self::assertSame('active', $resource->status);
+        self::assertSame('Congé maladie', $resource->reason);
+        self::assertEquals($replacement->createdAt, $resource->createdAt);
+        self::assertNull($resource->endedAt);
+    }
+
+    #[Test]
+    public function fromDomainMapsClassSubjectPairs(): void
+    {
+        $replacement = $this->createReplacement();
+
+        $resource = TeacherReplacementResource::fromDomain($replacement);
+
+        self::assertCount(1, $resource->classes);
+        self::assertSame(self::CLASS_ID, $resource->classes[0]['classId']);
+        self::assertSame(self::SUBJECT_ID, $resource->classes[0]['subjectId']);
+    }
+
+    #[Test]
+    public function fromDomainPreservesEndedAtWhenTerminated(): void
+    {
+        $replacement = $this->createReplacement();
+        $endedAt = new DateTimeImmutable('2026-03-20 14:00:00');
+        $replacement->terminer($endedAt);
+
+        $resource = TeacherReplacementResource::fromDomain($replacement);
+
+        self::assertSame('ended', $resource->status);
+        self::assertEquals($endedAt, $resource->endedAt);
+    }
+
+    #[Test]
+    public function fromDtoCreatesCorrectResource(): void
+    {
+        $startDate = new DateTimeImmutable('2026-03-01');
+        $endDate = new DateTimeImmutable('2026-03-31');
+
+        $dto = new ReplacementDto(
+            id: '550e8400-e29b-41d4-a716-446655440050',
+            replacedTeacherId: self::REPLACED_TEACHER_ID,
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            startDate: $startDate,
+            endDate: $endDate,
+            status: ReplacementStatus::ACTIVE->value,
+            classes: [
+                ['classId' => self::CLASS_ID, 'subjectId' => self::SUBJECT_ID],
+            ],
+            reason: 'Formation',
+        );
+
+        $resource = TeacherReplacementResource::fromDto($dto);
+
+        self::assertSame('550e8400-e29b-41d4-a716-446655440050', $resource->id);
+        self::assertSame(self::REPLACED_TEACHER_ID, $resource->replacedTeacherId);
+        self::assertSame(self::REPLACEMENT_TEACHER_ID, $resource->replacementTeacherId);
+        self::assertSame('2026-03-01', $resource->startDate);
+        self::assertSame('2026-03-31', $resource->endDate);
+        self::assertSame('active', $resource->status);
+        self::assertSame('Formation', $resource->reason);
+        self::assertCount(1, $resource->classes);
+        self::assertSame(self::CLASS_ID, $resource->classes[0]['classId']);
+        self::assertSame(self::SUBJECT_ID, $resource->classes[0]['subjectId']);
+    }
+
+    #[Test]
+    public function fromDtoPreservesNullReason(): void
+    {
+        $dto = new ReplacementDto(
+            id: '550e8400-e29b-41d4-a716-446655440050',
+            replacedTeacherId: self::REPLACED_TEACHER_ID,
+            replacementTeacherId: self::REPLACEMENT_TEACHER_ID,
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            status: ReplacementStatus::ACTIVE->value,
+            classes: [],
+            reason: null,
+        );
+
+        $resource = TeacherReplacementResource::fromDto($dto);
+
+        self::assertNull($resource->reason);
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: 'Congé maladie',
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Console/EndExpiredReplacementsCommandTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Console/EndExpiredReplacementsCommandTest.php
new file mode 100644
index 0000000..ea181c6
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Console/EndExpiredReplacementsCommandTest.php
@@ -0,0 +1,188 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Console;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Application\Command\EndReplacement\EndReplacementHandler;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\ReplacementStatus;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Console\EndExpiredReplacementsCommand;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\NullLogger;
+use Symfony\Component\Console\Tester\CommandTester;
+
+final class EndExpiredReplacementsCommandTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $repository;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-04-15 10:00:00');
+            }
+        };
+    }
+
+    #[Test]
+    public function itEndsExpiredReplacements(): void
+    {
+        $replacement = $this->createReplacement(
+            startDate: '2026-03-01',
+            endDate: '2026-03-31',
+        );
+        $this->repository->save($replacement);
+
+        $tester = $this->executeCommand();
+
+        self::assertSame(0, $tester->getStatusCode());
+        self::assertStringContainsString('1 remplacement(s) expiré(s) trouvé(s)', $tester->getDisplay());
+        self::assertStringContainsString('1 remplacement(s) terminé(s) avec succès.', $tester->getDisplay());
+    }
+
+    #[Test]
+    public function itHandlesNoExpiredReplacements(): void
+    {
+        $replacement = $this->createReplacement(
+            startDate: '2026-04-01',
+            endDate: '2026-04-30',
+        );
+        $this->repository->save($replacement);
+
+        $tester = $this->executeCommand();
+
+        self::assertSame(0, $tester->getStatusCode());
+        self::assertStringContainsString('Aucun remplacement expiré à traiter.', $tester->getDisplay());
+    }
+
+    #[Test]
+    public function itHandlesIndividualErrorsGracefully(): void
+    {
+        // The command's findExpired query uses one repository while the handler's
+        // get() uses another that holds an already-terminated copy of the same
+        // replacement, simulating a concurrent termination (race condition).
+        $commandRepository = new InMemoryTeacherReplacementRepository();
+        $activeReplacement = $this->createReplacement(
+            startDate: '2026-03-01',
+            endDate: '2026-03-31',
+        );
+        $commandRepository->save($activeReplacement);
+
+        $handlerRepository = new InMemoryTeacherReplacementRepository();
+        $terminatedReplacement = TeacherReplacement::reconstitute(
+            id: $activeReplacement->id,
+            tenantId: $activeReplacement->tenantId,
+            replacedTeacherId: $activeReplacement->replacedTeacherId,
+            replacementTeacherId: $activeReplacement->replacementTeacherId,
+            startDate: $activeReplacement->startDate,
+            endDate: $activeReplacement->endDate,
+            status: ReplacementStatus::ENDED,
+            classes: $activeReplacement->classes,
+            reason: $activeReplacement->reason,
+            createdBy: $activeReplacement->createdBy,
+            createdAt: $activeReplacement->createdAt,
+            endedAt: new DateTimeImmutable('2026-03-31'),
+            updatedAt: new DateTimeImmutable('2026-03-31'),
+        );
+        $handlerRepository->save($terminatedReplacement);
+
+        $handler = new EndReplacementHandler($handlerRepository, $this->clock);
+
+        $command = new EndExpiredReplacementsCommand(
+            $commandRepository,
+            $handler,
+            $this->clock,
+            new NullLogger(),
+        );
+
+        $tester = new CommandTester($command);
+        $tester->execute([]);
+
+        self::assertSame(0, $tester->getStatusCode());
+        self::assertStringContainsString('1 remplacement(s) expiré(s) trouvé(s)', $tester->getDisplay());
+        self::assertStringContainsString('déjà terminé', $tester->getDisplay());
+        self::assertStringContainsString('0 remplacement(s) terminé(s) avec succès.', $tester->getDisplay());
+    }
+
+    #[Test]
+    public function itOutputsCorrectMessagesForMultipleReplacements(): void
+    {
+        $replacement1 = $this->createReplacement(
+            startDate: '2026-02-01',
+            endDate: '2026-02-28',
+        );
+        $replacement2 = $this->createReplacement(
+            startDate: '2026-03-01',
+            endDate: '2026-03-31',
+            replacementTeacherId: '550e8400-e29b-41d4-a716-446655440012',
+        );
+        $this->repository->save($replacement1);
+        $this->repository->save($replacement2);
+
+        $tester = $this->executeCommand();
+
+        self::assertSame(0, $tester->getStatusCode());
+        self::assertStringContainsString('2 remplacement(s) expiré(s) trouvé(s)', $tester->getDisplay());
+        self::assertStringContainsString('2 remplacement(s) terminé(s) avec succès.', $tester->getDisplay());
+    }
+
+    private function executeCommand(): CommandTester
+    {
+        $handler = new EndReplacementHandler($this->repository, $this->clock);
+
+        $command = new EndExpiredReplacementsCommand(
+            $this->repository,
+            $handler,
+            $this->clock,
+            new NullLogger(),
+        );
+
+        $tester = new CommandTester($command);
+        $tester->execute([]);
+
+        return $tester;
+    }
+
+    private function createReplacement(
+        string $startDate = '2026-03-01',
+        string $endDate = '2026-03-31',
+        string $replacementTeacherId = self::REPLACEMENT_TEACHER_ID,
+    ): TeacherReplacement {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString($replacementTeacherId),
+            startDate: new DateTimeImmutable($startDate),
+            endDate: new DateTimeImmutable($endDate),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Persistence/InMemory/InMemoryTeacherReplacementRepositoryTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Persistence/InMemory/InMemoryTeacherReplacementRepositoryTest.php
new file mode 100644
index 0000000..a36e251
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Persistence/InMemory/InMemoryTeacherReplacementRepositoryTest.php
@@ -0,0 +1,265 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Persistence\InMemory;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\UserId;
+use App\Scolarite\Domain\Exception\RemplacementNotFoundException;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacementId;
+use App\Scolarite\Infrastructure\Persistence\InMemory\InMemoryTeacherReplacementRepository;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class InMemoryTeacherReplacementRepositoryTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string OTHER_TENANT_ID = '550e8400-e29b-41d4-a716-446655440002';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+    private const string OTHER_REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440012';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string OTHER_CLASS_ID = '550e8400-e29b-41d4-a716-446655440021';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+    private const string OTHER_SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440031';
+    private const string CREATED_BY_ID = '550e8400-e29b-41d4-a716-446655440099';
+
+    private InMemoryTeacherReplacementRepository $repository;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryTeacherReplacementRepository();
+    }
+
+    #[Test]
+    public function saveAndGet(): void
+    {
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $found = $this->repository->get($replacement->id, $replacement->tenantId);
+
+        self::assertSame($replacement, $found);
+    }
+
+    #[Test]
+    public function findByIdReturnsNullWhenNotFound(): void
+    {
+        $result = $this->repository->findById(
+            TeacherReplacementId::fromString('550e8400-e29b-41d4-a716-446655440099'),
+            TenantId::fromString(self::TENANT_ID),
+        );
+
+        self::assertNull($result);
+    }
+
+    #[Test]
+    public function findByIdReturnsNullWhenTenantDoesNotMatch(): void
+    {
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $this->repository->findById(
+            $replacement->id,
+            TenantId::fromString(self::OTHER_TENANT_ID),
+        );
+
+        self::assertNull($result);
+    }
+
+    #[Test]
+    public function getThrowsWhenNotFound(): void
+    {
+        $this->expectException(RemplacementNotFoundException::class);
+
+        $this->repository->get(
+            TeacherReplacementId::fromString('550e8400-e29b-41d4-a716-446655440099'),
+            TenantId::fromString(self::TENANT_ID),
+        );
+    }
+
+    #[Test]
+    public function findActiveByTenantReturnsOnlyActiveInDateRange(): void
+    {
+        $activeReplacement = $this->createReplacement();
+        $this->repository->save($activeReplacement);
+
+        $endedReplacement = $this->createReplacement(
+            replacementTeacherId: self::OTHER_REPLACEMENT_TEACHER_ID,
+        );
+        $endedReplacement->terminer(new DateTimeImmutable('2026-03-10'));
+        $this->repository->save($endedReplacement);
+
+        $result = $this->repository->findActiveByTenant(
+            TenantId::fromString(self::TENANT_ID),
+            new DateTimeImmutable('2026-03-15'),
+        );
+
+        self::assertCount(1, $result);
+        self::assertSame($activeReplacement, $result[0]);
+    }
+
+    #[Test]
+    public function findActiveByTenantExcludesExpiredReplacements(): void
+    {
+        $replacement = $this->createReplacement(
+            startDate: '2026-02-01',
+            endDate: '2026-02-28',
+        );
+        $this->repository->save($replacement);
+
+        $result = $this->repository->findActiveByTenant(
+            TenantId::fromString(self::TENANT_ID),
+            new DateTimeImmutable('2026-03-15'),
+        );
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function findActiveByReplacementTeacherFiltersCorrectly(): void
+    {
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $otherReplacement = $this->createReplacement(
+            replacementTeacherId: self::OTHER_REPLACEMENT_TEACHER_ID,
+        );
+        $this->repository->save($otherReplacement);
+
+        $result = $this->repository->findActiveByReplacementTeacher(
+            UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            TenantId::fromString(self::TENANT_ID),
+            new DateTimeImmutable('2026-03-15'),
+        );
+
+        self::assertCount(1, $result);
+        self::assertSame($replacement, $result[0]);
+    }
+
+    #[Test]
+    public function findActiveByReplacementTeacherExcludesInactiveReplacements(): void
+    {
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $this->repository->findActiveByReplacementTeacher(
+            UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            TenantId::fromString(self::TENANT_ID),
+            new DateTimeImmutable('2026-04-15'),
+        );
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function findActiveReplacementMatchesClassSubjectPair(): void
+    {
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $this->repository->findActiveReplacement(
+            UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            ClassId::fromString(self::CLASS_ID),
+            SubjectId::fromString(self::SUBJECT_ID),
+            new DateTimeImmutable('2026-03-15'),
+            TenantId::fromString(self::TENANT_ID),
+        );
+
+        self::assertNotNull($result);
+        self::assertSame($replacement, $result);
+    }
+
+    #[Test]
+    public function findActiveReplacementReturnsNullForNonMatchingPair(): void
+    {
+        $replacement = $this->createReplacement();
+        $this->repository->save($replacement);
+
+        $result = $this->repository->findActiveReplacement(
+            UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            ClassId::fromString(self::OTHER_CLASS_ID),
+            SubjectId::fromString(self::OTHER_SUBJECT_ID),
+            new DateTimeImmutable('2026-03-15'),
+            TenantId::fromString(self::TENANT_ID),
+        );
+
+        self::assertNull($result);
+    }
+
+    #[Test]
+    public function findExpiredReturnsOnlyExpiredAcrossTenants(): void
+    {
+        $expiredReplacement = $this->createReplacement(
+            startDate: '2026-02-01',
+            endDate: '2026-02-28',
+        );
+        $this->repository->save($expiredReplacement);
+
+        $expiredOtherTenant = $this->createReplacement(
+            tenantId: self::OTHER_TENANT_ID,
+            startDate: '2026-02-01',
+            endDate: '2026-02-28',
+            replacementTeacherId: self::OTHER_REPLACEMENT_TEACHER_ID,
+        );
+        $this->repository->save($expiredOtherTenant);
+
+        $activeReplacement = $this->createReplacement(
+            startDate: '2026-03-01',
+            endDate: '2026-04-30',
+            replacementTeacherId: '550e8400-e29b-41d4-a716-446655440013',
+        );
+        $this->repository->save($activeReplacement);
+
+        $result = $this->repository->findExpired(new DateTimeImmutable('2026-03-15'));
+
+        self::assertCount(2, $result);
+        self::assertContains($expiredReplacement, $result);
+        self::assertContains($expiredOtherTenant, $result);
+    }
+
+    #[Test]
+    public function findExpiredExcludesAlreadyEndedReplacements(): void
+    {
+        $replacement = $this->createReplacement(
+            startDate: '2026-02-01',
+            endDate: '2026-02-28',
+        );
+        $replacement->terminer(new DateTimeImmutable('2026-02-28'));
+        $this->repository->save($replacement);
+
+        $result = $this->repository->findExpired(new DateTimeImmutable('2026-03-15'));
+
+        self::assertSame([], $result);
+    }
+
+    private function createReplacement(
+        string $tenantId = self::TENANT_ID,
+        string $startDate = '2026-03-01',
+        string $endDate = '2026-03-31',
+        string $replacementTeacherId = self::REPLACEMENT_TEACHER_ID,
+    ): TeacherReplacement {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString($tenantId),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString($replacementTeacherId),
+            startDate: new DateTimeImmutable($startDate),
+            endDate: new DateTimeImmutable($endDate),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString(self::CLASS_ID),
+                    SubjectId::fromString(self::SUBJECT_ID),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString(self::CREATED_BY_ID),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Scolarite/Infrastructure/Security/TeacherReplacementVoterTest.php b/backend/tests/Unit/Scolarite/Infrastructure/Security/TeacherReplacementVoterTest.php
new file mode 100644
index 0000000..cf6dd6b
--- /dev/null
+++ b/backend/tests/Unit/Scolarite/Infrastructure/Security/TeacherReplacementVoterTest.php
@@ -0,0 +1,250 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Infrastructure\Security;
+
+use App\Administration\Domain\Model\SchoolClass\ClassId;
+use App\Administration\Domain\Model\Subject\SubjectId;
+use App\Administration\Domain\Model\User\Role;
+use App\Administration\Domain\Model\User\UserId;
+use App\Administration\Infrastructure\Security\SecurityUser;
+use App\Scolarite\Domain\Model\TeacherReplacement\ClassSubjectPair;
+use App\Scolarite\Domain\Model\TeacherReplacement\TeacherReplacement;
+use App\Scolarite\Infrastructure\Security\TeacherReplacementVoter;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
+use Symfony\Component\Security\Core\Authorization\Voter\Voter;
+use Symfony\Component\Security\Core\User\UserInterface;
+
+final class TeacherReplacementVoterTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440002';
+    private const string REPLACED_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string REPLACEMENT_TEACHER_ID = '550e8400-e29b-41d4-a716-446655440011';
+
+    private TeacherReplacementVoter $voter;
+
+    protected function setUp(): void
+    {
+        $this->voter = new TeacherReplacementVoter();
+    }
+
+    #[Test]
+    public function itAbstainsForUnrelatedAttributes(): void
+    {
+        $token = $this->tokenWithSecurityUser(Role::ADMIN->value);
+
+        $result = $this->voter->vote($token, null, ['SOME_OTHER_ATTRIBUTE']);
+
+        self::assertSame(Voter::ACCESS_ABSTAIN, $result);
+    }
+
+    #[Test]
+    public function itDeniesAccessToUnauthenticatedUsers(): void
+    {
+        $token = $this->createMock(TokenInterface::class);
+        $token->method('getUser')->willReturn(null);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    #[Test]
+    public function itDeniesAccessToNonSecurityUserInstances(): void
+    {
+        $user = $this->createMock(UserInterface::class);
+        $user->method('getRoles')->willReturn([Role::ADMIN->value]);
+
+        $token = $this->createMock(TokenInterface::class);
+        $token->method('getUser')->willReturn($user);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    // --- VIEW ---
+
+    #[Test]
+    #[DataProvider('adminRolesProvider')]
+    public function itGrantsViewToAdminRoles(string $role): void
+    {
+        $token = $this->tokenWithSecurityUser($role);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_GRANTED, $result);
+    }
+
+    #[Test]
+    public function itGrantsViewToReplacedTeacher(): void
+    {
+        $token = $this->tokenWithSecurityUser(Role::PROF->value, self::REPLACED_TEACHER_ID);
+        $replacement = $this->createReplacement();
+
+        $result = $this->voter->vote($token, $replacement, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_GRANTED, $result);
+    }
+
+    #[Test]
+    public function itGrantsViewToReplacementTeacher(): void
+    {
+        $token = $this->tokenWithSecurityUser(Role::PROF->value, self::REPLACEMENT_TEACHER_ID);
+        $replacement = $this->createReplacement();
+
+        $result = $this->voter->vote($token, $replacement, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_GRANTED, $result);
+    }
+
+    #[Test]
+    public function itDeniesViewToUninvolvedTeacher(): void
+    {
+        $token = $this->tokenWithSecurityUser(Role::PROF->value, '550e8400-e29b-41d4-a716-446655440099');
+        $replacement = $this->createReplacement();
+
+        $result = $this->voter->vote($token, $replacement, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    #[Test]
+    public function itDeniesViewToTeacherWithoutSubject(): void
+    {
+        $token = $this->tokenWithSecurityUser(Role::PROF->value, self::REPLACED_TEACHER_ID);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    #[Test]
+    #[DataProvider('nonStaffRolesProvider')]
+    public function itDeniesViewToNonStaffRoles(string $role): void
+    {
+        $token = $this->tokenWithSecurityUser($role);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::VIEW]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    // --- CREATE ---
+
+    #[Test]
+    #[DataProvider('adminRolesProvider')]
+    public function itGrantsCreateToAdminRoles(string $role): void
+    {
+        $token = $this->tokenWithSecurityUser($role);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::CREATE]);
+
+        self::assertSame(Voter::ACCESS_GRANTED, $result);
+    }
+
+    #[Test]
+    #[DataProvider('nonAdminRolesProvider')]
+    public function itDeniesCreateToNonAdminRoles(string $role): void
+    {
+        $token = $this->tokenWithSecurityUser($role);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::CREATE]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    // --- DELETE ---
+
+    #[Test]
+    #[DataProvider('adminRolesProvider')]
+    public function itGrantsDeleteToAdminRoles(string $role): void
+    {
+        $token = $this->tokenWithSecurityUser($role);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::DELETE]);
+
+        self::assertSame(Voter::ACCESS_GRANTED, $result);
+    }
+
+    #[Test]
+    #[DataProvider('nonAdminRolesProvider')]
+    public function itDeniesDeleteToNonAdminRoles(string $role): void
+    {
+        $token = $this->tokenWithSecurityUser($role);
+
+        $result = $this->voter->vote($token, null, [TeacherReplacementVoter::DELETE]);
+
+        self::assertSame(Voter::ACCESS_DENIED, $result);
+    }
+
+    // --- Data Providers ---
+
+    /** @return iterable<string, array{string}> */
+    public static function adminRolesProvider(): iterable
+    {
+        yield 'SUPER_ADMIN' => [Role::SUPER_ADMIN->value];
+        yield 'ADMIN' => [Role::ADMIN->value];
+    }
+
+    /** @return iterable<string, array{string}> */
+    public static function nonAdminRolesProvider(): iterable
+    {
+        yield 'PROF' => [Role::PROF->value];
+        yield 'VIE_SCOLAIRE' => [Role::VIE_SCOLAIRE->value];
+        yield 'SECRETARIAT' => [Role::SECRETARIAT->value];
+        yield 'PARENT' => [Role::PARENT->value];
+        yield 'ELEVE' => [Role::ELEVE->value];
+    }
+
+    /** @return iterable<string, array{string}> */
+    public static function nonStaffRolesProvider(): iterable
+    {
+        yield 'PARENT' => [Role::PARENT->value];
+        yield 'ELEVE' => [Role::ELEVE->value];
+    }
+
+    private function createReplacement(): TeacherReplacement
+    {
+        return TeacherReplacement::designer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            replacedTeacherId: UserId::fromString(self::REPLACED_TEACHER_ID),
+            replacementTeacherId: UserId::fromString(self::REPLACEMENT_TEACHER_ID),
+            startDate: new DateTimeImmutable('2026-03-01'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+            classes: [
+                new ClassSubjectPair(
+                    ClassId::fromString('550e8400-e29b-41d4-a716-446655440020'),
+                    SubjectId::fromString('550e8400-e29b-41d4-a716-446655440030'),
+                ),
+            ],
+            reason: null,
+            createdBy: UserId::fromString('550e8400-e29b-41d4-a716-446655440099'),
+            now: new DateTimeImmutable('2026-02-15 10:00:00'),
+        );
+    }
+
+    private function tokenWithSecurityUser(
+        string $role,
+        string $userId = '550e8400-e29b-41d4-a716-446655440001',
+    ): TokenInterface {
+        $securityUser = new SecurityUser(
+            UserId::fromString($userId),
+            'test@example.com',
+            'hashed_password',
+            TenantId::fromString(self::TENANT_ID),
+            [$role],
+        );
+
+        $token = $this->createMock(TokenInterface::class);
+        $token->method('getUser')->willReturn($securityUser);
+
+        return $token;
+    }
+}
diff --git a/frontend/e2e/admin-responsive-nav.spec.ts b/frontend/e2e/admin-responsive-nav.spec.ts
new file mode 100644
index 0000000..4e1816d
--- /dev/null
+++ b/frontend/e2e/admin-responsive-nav.spec.ts
@@ -0,0 +1,222 @@
+import { test, expect } from '@playwright/test';
+import { execSync } from 'child_process';
+import { join, dirname } from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const baseUrl = process.env.PLAYWRIGHT_BASE_URL || 'http://localhost:4173';
+const urlMatch = baseUrl.match(/:(\d+)$/);
+const PORT = urlMatch ? urlMatch[1] : '4173';
+const ALPHA_URL = `http://ecole-alpha.classeo.local:${PORT}`;
+
+const ADMIN_EMAIL = 'e2e-responsive-nav@example.com';
+const ADMIN_PASSWORD = 'ResponsiveNav123';
+
+const projectRoot = join(__dirname, '../..');
+const composeFile = join(projectRoot, 'compose.yaml');
+
+test.describe('Admin Responsive Navigation', () => {
+	test.beforeAll(async () => {
+		execSync(
+			`docker compose -f "${composeFile}" exec -T php php bin/console app:dev:create-test-user --tenant=ecole-alpha --email=${ADMIN_EMAIL} --password=${ADMIN_PASSWORD} --role=ROLE_ADMIN 2>&1`,
+			{ encoding: 'utf-8' }
+		);
+	});
+
+	async function loginAsAdmin(page: import('@playwright/test').Page) {
+		await page.goto(`${ALPHA_URL}/login`);
+		await page.locator('#email').fill(ADMIN_EMAIL);
+		await page.locator('#password').fill(ADMIN_PASSWORD);
+		await Promise.all([
+			page.waitForURL(/\/dashboard/, { timeout: 30000 }),
+			page.getByRole('button', { name: /se connecter/i }).click()
+		]);
+	}
+
+	// =========================================================================
+	// MOBILE (375×667)
+	// =========================================================================
+	test.describe('Mobile (375×667)', () => {
+		test.use({ viewport: { width: 375, height: 667 } });
+
+		test('shows hamburger button and hides desktop nav', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const hamburger = page.getByRole('button', { name: /ouvrir le menu/i });
+			await expect(hamburger).toBeVisible();
+
+			const desktopNav = page.locator('.desktop-nav');
+			await expect(desktopNav).not.toBeVisible();
+		});
+
+		test('displays current section label', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const label = page.locator('.mobile-section-label');
+			await expect(label).toBeVisible();
+			await expect(label).toHaveText('Utilisateurs');
+		});
+
+		test('opens and closes menu via hamburger button', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const hamburger = page.getByRole('button', { name: /ouvrir le menu/i });
+
+			// Open
+			await hamburger.click();
+			const drawer = page.locator('[role="dialog"][aria-modal="true"]');
+			await expect(drawer).toBeVisible();
+
+			// Close via × button
+			const closeButton = page.getByRole('button', { name: /fermer le menu/i });
+			await closeButton.click();
+			await expect(drawer).not.toBeVisible();
+		});
+
+		test('closes menu on overlay click', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			await page.getByRole('button', { name: /ouvrir le menu/i }).click();
+			const drawer = page.locator('[role="dialog"][aria-modal="true"]');
+			await expect(drawer).toBeVisible();
+
+			// Click overlay (outside drawer)
+			const overlay = page.locator('.mobile-overlay');
+			await overlay.click({ position: { x: 350, y: 300 } });
+			await expect(drawer).not.toBeVisible();
+		});
+
+		test('closes menu on Escape key', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			await page.getByRole('button', { name: /ouvrir le menu/i }).click();
+			const drawer = page.locator('[role="dialog"][aria-modal="true"]');
+			await expect(drawer).toBeVisible();
+
+			await page.keyboard.press('Escape');
+			await expect(drawer).not.toBeVisible();
+		});
+
+		test('shows active state for current section in mobile menu', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			await page.getByRole('button', { name: /ouvrir le menu/i }).click();
+			const drawer = page.locator('[role="dialog"][aria-modal="true"]');
+			await expect(drawer).toBeVisible();
+
+			const activeLink = drawer.locator('.mobile-nav-link.active');
+			await expect(activeLink).toHaveText('Utilisateurs');
+		});
+
+		test('navigates via mobile menu and closes it', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			// Open menu and click Classes
+			await page.getByRole('button', { name: /ouvrir le menu/i }).click();
+			const drawer = page.locator('[role="dialog"][aria-modal="true"]');
+			await expect(drawer).toBeVisible();
+
+			await drawer.getByRole('link', { name: 'Classes' }).click();
+
+			// Menu should close and page should navigate
+			await expect(drawer).not.toBeVisible();
+			await expect(page).toHaveURL(/\/admin\/classes/);
+
+			// Section label should update
+			const label = page.locator('.mobile-section-label');
+			await expect(label).toHaveText('Classes');
+		});
+	});
+
+	// =========================================================================
+	// TABLET (768×1024)
+	// =========================================================================
+	test.describe('Tablet (768×1024)', () => {
+		test.use({ viewport: { width: 768, height: 1024 } });
+
+		test('shows hamburger button (below 1200px)', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const hamburger = page.getByRole('button', { name: /ouvrir le menu/i });
+			await expect(hamburger).toBeVisible();
+
+			const desktopNav = page.locator('.desktop-nav');
+			await expect(desktopNav).not.toBeVisible();
+		});
+
+		test('drawer opens and works', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			await page.getByRole('button', { name: /ouvrir le menu/i }).click();
+			const drawer = page.locator('[role="dialog"][aria-modal="true"]');
+			await expect(drawer).toBeVisible();
+
+			// All nav links should be visible in drawer
+			await expect(drawer.getByRole('link', { name: 'Utilisateurs' })).toBeVisible();
+			await expect(drawer.getByRole('link', { name: 'Classes' })).toBeVisible();
+			await expect(drawer.getByRole('link', { name: 'Matières' })).toBeVisible();
+		});
+	});
+
+	// =========================================================================
+	// DESKTOP (1280×800)
+	// =========================================================================
+	test.describe('Desktop (1280×800)', () => {
+		test.use({ viewport: { width: 1280, height: 800 } });
+
+		test('hides hamburger and shows desktop nav', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const hamburger = page.getByRole('button', { name: /ouvrir le menu/i });
+			await expect(hamburger).not.toBeVisible();
+
+			const desktopNav = page.locator('.desktop-nav');
+			await expect(desktopNav).toBeVisible();
+		});
+
+		test('desktop nav shows all navigation links', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const nav = page.locator('.desktop-nav');
+			await expect(nav.getByRole('link', { name: 'Utilisateurs' })).toBeVisible();
+			await expect(nav.getByRole('link', { name: 'Classes' })).toBeVisible();
+			await expect(nav.getByRole('link', { name: 'Matières' })).toBeVisible();
+			await expect(nav.getByRole('link', { name: 'Affectations' })).toBeVisible();
+			await expect(nav.getByRole('link', { name: 'Périodes' })).toBeVisible();
+			await expect(nav.getByRole('link', { name: 'Pédagogie' })).toBeVisible();
+		});
+
+		test('hides mobile section label', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/users`);
+			await page.waitForLoadState('networkidle');
+
+			const label = page.locator('.mobile-section-label');
+			await expect(label).not.toBeVisible();
+		});
+	});
+});
diff --git a/frontend/e2e/periods.spec.ts b/frontend/e2e/periods.spec.ts
index 532e6d7..56d7e92 100644
--- a/frontend/e2e/periods.spec.ts
+++ b/frontend/e2e/periods.spec.ts
@@ -284,12 +284,12 @@ test.describe('Periods Management (Story 2.3)', () => {
 	// Navigation
 	// ============================================================================
 	test.describe('Navigation', () => {
-		test('can access periods page from admin dashboard', async ({ page }) => {
+		test('can access periods page from admin navigation', async ({ page }) => {
 			await loginAsAdmin(page);
 			await page.goto(`${ALPHA_URL}/admin`);
 
-			// Click on periods card
-			await page.getByRole('link', { name: /périodes scolaires/i }).click();
+			// Click on periods link in the admin navigation
+			await page.getByRole('link', { name: /périodes/i }).click();
 
 			await expect(page).toHaveURL(/\/admin\/academic-year\/periods/);
 			await expect(page.getByRole('heading', { name: /périodes scolaires/i })).toBeVisible();
diff --git a/frontend/e2e/role-access-control.spec.ts b/frontend/e2e/role-access-control.spec.ts
index 4914d53..09c176c 100644
--- a/frontend/e2e/role-access-control.spec.ts
+++ b/frontend/e2e/role-access-control.spec.ts
@@ -96,9 +96,10 @@ test.describe('Role-Based Access Control [P0]', () => {
 			await loginAs(page, ADMIN_EMAIL, ADMIN_PASSWORD);
 			await page.goto(`${ALPHA_URL}/admin`);
 
-			await expect(page).toHaveURL(/\/admin/);
+			// /admin redirects to /admin/users
+			await expect(page).toHaveURL(/\/admin\/users/);
 			await expect(
-				page.getByRole('heading', { name: /administration/i })
+				page.getByRole('heading', { name: /gestion des utilisateurs/i })
 			).toBeVisible({ timeout: 10000 });
 		});
 	});
@@ -191,8 +192,8 @@ test.describe('Role-Based Access Control [P0]', () => {
 			await loginAs(page, ADMIN_EMAIL, ADMIN_PASSWORD);
 			await page.goto(`${ALPHA_URL}/admin`);
 
-			// Admin layout should show navigation links (scoped to header nav to avoid action cards)
-			const nav = page.locator('.header-nav');
+			// Admin layout should show navigation links (scoped to desktop nav to avoid action cards)
+			const nav = page.locator('.desktop-nav');
 			await expect(nav.getByRole('link', { name: 'Utilisateurs' })).toBeVisible({ timeout: 15000 });
 			await expect(nav.getByRole('link', { name: 'Classes' })).toBeVisible();
 		});
diff --git a/frontend/e2e/teacher-replacements.spec.ts b/frontend/e2e/teacher-replacements.spec.ts
new file mode 100644
index 0000000..ce10f71
--- /dev/null
+++ b/frontend/e2e/teacher-replacements.spec.ts
@@ -0,0 +1,278 @@
+import { test, expect } from '@playwright/test';
+import { execSync } from 'child_process';
+import { join, dirname } from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const baseUrl = process.env.PLAYWRIGHT_BASE_URL || 'http://localhost:4173';
+const urlMatch = baseUrl.match(/:(\d+)$/);
+const PORT = urlMatch ? urlMatch[1] : '4173';
+const ALPHA_URL = `http://ecole-alpha.classeo.local:${PORT}`;
+
+const ADMIN_EMAIL = 'e2e-replacements-admin@example.com';
+const ADMIN_PASSWORD = 'ReplacementsTest123';
+const TENANT_ID = 'a1b2c3d4-e5f6-7890-abcd-ef1234567890';
+
+const projectRoot = join(__dirname, '../..');
+const composeFile = join(projectRoot, 'compose.yaml');
+
+function runCommand(sql: string) {
+	execSync(
+		`docker compose -f "${composeFile}" exec -T php php bin/console dbal:run-sql "${sql}" 2>&1`,
+		{ encoding: 'utf-8' }
+	);
+}
+
+function resolveDeterministicIds(): { schoolId: string; academicYearId: string } {
+	const output = execSync(
+		`docker compose -f "${composeFile}" exec -T php php -r '` +
+			`require "/app/vendor/autoload.php"; ` +
+			`$t="${TENANT_ID}"; $ns="6ba7b814-9dad-11d1-80b4-00c04fd430c8"; ` +
+			`echo Ramsey\\Uuid\\Uuid::uuid5($ns,"school-$t")->toString()."\\n"; ` +
+			`$m=(int)date("n"); $s=$m>=9?(int)date("Y"):(int)date("Y")-1; $e=$s+1; ` +
+			`echo Ramsey\\Uuid\\Uuid::uuid5($ns,"$t:$s-$e")->toString();` +
+			`' 2>&1`,
+		{ encoding: 'utf-8' }
+	).trim();
+	const [schoolId, academicYearId] = output.split('\n');
+	return { schoolId, academicYearId };
+}
+
+async function loginAsAdmin(page: import('@playwright/test').Page) {
+	await page.goto(`${ALPHA_URL}/login`);
+	await page.locator('#email').fill(ADMIN_EMAIL);
+	await page.locator('#password').fill(ADMIN_PASSWORD);
+	await Promise.all([
+		page.waitForURL(/\/dashboard/, { timeout: 30000 }),
+		page.getByRole('button', { name: /se connecter/i }).click()
+	]);
+}
+
+async function waitForPageReady(page: import('@playwright/test').Page) {
+	await expect(
+		page.getByRole('heading', { name: /remplacements enseignants/i })
+	).toBeVisible({ timeout: 15000 });
+	await expect(
+		page.locator('.empty-state, .replacements-table, .alert-error')
+	).toBeVisible({ timeout: 15000 });
+}
+
+async function openCreateDialog(page: import('@playwright/test').Page) {
+	const button = page.getByRole('button', { name: /nouveau remplacement/i }).first();
+	await expect(button).toBeEnabled();
+	await button.click();
+	await expect(page.getByRole('dialog')).toBeVisible({ timeout: 10000 });
+}
+
+function getTodayDate(): string {
+	return new Date().toISOString().split('T')[0];
+}
+
+function getFutureDate(days: number): string {
+	const date = new Date();
+	date.setDate(date.getDate() + days);
+	return date.toISOString().split('T')[0];
+}
+
+test.describe('Teacher Replacements (Story 2.9)', () => {
+	test.beforeAll(async () => {
+		execSync(
+			`docker compose -f "${composeFile}" exec -T php php bin/console app:dev:create-test-user --tenant=ecole-alpha --email=${ADMIN_EMAIL} --password=${ADMIN_PASSWORD} --role=ROLE_ADMIN 2>&1`,
+			{ encoding: 'utf-8' }
+		);
+
+		execSync(
+			`docker compose -f "${composeFile}" exec -T php php bin/console app:dev:create-test-user --tenant=ecole-alpha --email=e2e-replaced-teacher@example.com --password=TeacherTest123 --role=ROLE_PROF 2>&1`,
+			{ encoding: 'utf-8' }
+		);
+
+		execSync(
+			`docker compose -f "${composeFile}" exec -T php php bin/console app:dev:create-test-user --tenant=ecole-alpha --email=e2e-replacement-teacher@example.com --password=TeacherTest123 --role=ROLE_PROF 2>&1`,
+			{ encoding: 'utf-8' }
+		);
+
+		const { schoolId, academicYearId } = resolveDeterministicIds();
+
+		runCommand(
+			`INSERT INTO school_classes (id, tenant_id, school_id, academic_year_id, name, level, status, created_at, updated_at) VALUES (gen_random_uuid(), '${TENANT_ID}', '${schoolId}', '${academicYearId}', 'E2E-Repl-6B', '6ème', 'active', NOW(), NOW()) ON CONFLICT DO NOTHING`
+		);
+
+		runCommand(
+			`INSERT INTO subjects (id, tenant_id, school_id, name, code, status, created_at, updated_at) VALUES (gen_random_uuid(), '${TENANT_ID}', '${schoolId}', 'E2E-Repl-Français', 'E2EFRA', 'active', NOW(), NOW()) ON CONFLICT DO NOTHING`
+		);
+	});
+
+	test.beforeEach(async () => {
+		try {
+			runCommand(`DELETE FROM replacement_classes WHERE replacement_id IN (SELECT id FROM teacher_replacements WHERE tenant_id = '${TENANT_ID}')`);
+			runCommand(`DELETE FROM teacher_replacements WHERE tenant_id = '${TENANT_ID}'`);
+		} catch {
+			// Tables may not exist yet if migration hasn't run
+		}
+	});
+
+	// ============================================================================
+	// Navigation
+	// ============================================================================
+	test.describe('Navigation', () => {
+		test('replacements link appears in admin navigation', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin`);
+
+			const navLink = page.getByRole('link', { name: /remplacements/i });
+			await expect(navLink).toBeVisible({ timeout: 15000 });
+		});
+
+		test('can navigate to replacements page', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/replacements`);
+
+			await expect(page.getByRole('heading', { name: /remplacements enseignants/i })).toBeVisible({ timeout: 15000 });
+		});
+	});
+
+	// ============================================================================
+	// Empty State
+	// ============================================================================
+	test.describe('Empty State', () => {
+		test('shows empty state when no replacements exist', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/replacements`);
+
+			await waitForPageReady(page);
+			await expect(page.getByText(/aucun remplacement actif/i)).toBeVisible({ timeout: 10000 });
+		});
+	});
+
+	// ============================================================================
+	// AC1: Create Replacement
+	// ============================================================================
+	test.describe('AC1: Create Replacement', () => {
+		test('can create a new replacement', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/replacements`);
+			await waitForPageReady(page);
+
+			await openCreateDialog(page);
+
+			// Select replaced teacher
+			const replacedSelect = page.locator('#replaced-teacher');
+			await expect(replacedSelect).toBeVisible();
+			await replacedSelect.selectOption({ index: 1 });
+
+			// Select replacement teacher (different from replaced)
+			const replacementSelect = page.locator('#replacement-teacher');
+			await expect(replacementSelect).toBeVisible();
+			const replacementOptions = replacementSelect.locator('option');
+			const count = await replacementOptions.count();
+			// Select a different teacher (index 1 should work since replaced teacher is filtered out)
+			if (count > 1) {
+				await replacementSelect.selectOption({ index: 1 });
+			}
+
+			// Set dates
+			await page.locator('#start-date').fill(getTodayDate());
+			await page.locator('#end-date').fill(getFutureDate(30));
+
+			// Select class and subject
+			const firstClassSelect = page.locator('.class-pair-row select').first();
+			await firstClassSelect.selectOption({ index: 1 });
+			const firstSubjectSelect = page.locator('.class-pair-row select').nth(1);
+			await firstSubjectSelect.selectOption({ index: 1 });
+
+			// Submit
+			await page.getByRole('button', { name: /désigner le remplaçant/i }).click();
+
+			await expect(page.getByRole('dialog')).not.toBeVisible({ timeout: 10000 });
+			await expect(page.getByText(/remplacement créé/i)).toBeVisible({ timeout: 10000 });
+
+			// Verify table shows the replacement
+			const table = page.locator('.replacements-table');
+			await expect(table).toBeVisible({ timeout: 10000 });
+			const rows = table.locator('tbody tr');
+			const rowCount = await rows.count();
+			expect(rowCount).toBeGreaterThanOrEqual(1);
+		});
+
+		test('cancel closes the modal without creating', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/replacements`);
+			await waitForPageReady(page);
+
+			await openCreateDialog(page);
+
+			await page.getByRole('button', { name: /annuler/i }).click();
+			await expect(page.getByRole('dialog')).not.toBeVisible({ timeout: 5000 });
+		});
+	});
+
+	// ============================================================================
+	// AC3: End Replacement
+	// ============================================================================
+	test.describe('AC3: End Replacement', () => {
+		test('can end an active replacement', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/replacements`);
+			await waitForPageReady(page);
+
+			// First create a replacement
+			await openCreateDialog(page);
+			await page.locator('#replaced-teacher').selectOption({ index: 1 });
+			await page.locator('#replacement-teacher').selectOption({ index: 1 });
+			await page.locator('#start-date').fill(getTodayDate());
+			await page.locator('#end-date').fill(getFutureDate(30));
+			const firstClassSelect = page.locator('.class-pair-row select').first();
+			await firstClassSelect.selectOption({ index: 1 });
+			const firstSubjectSelect = page.locator('.class-pair-row select').nth(1);
+			await firstSubjectSelect.selectOption({ index: 1 });
+			await page.getByRole('button', { name: /désigner le remplaçant/i }).click();
+			await expect(page.getByRole('dialog')).not.toBeVisible({ timeout: 10000 });
+
+			// Now end it
+			const endButton = page.locator('.btn-remove').first();
+			await endButton.click();
+
+			const confirmDialog = page.getByRole('alertdialog');
+			await expect(confirmDialog).toBeVisible({ timeout: 5000 });
+			await expect(page.getByText(/perdra immédiatement l'accès/i)).toBeVisible();
+
+			await confirmDialog.getByRole('button', { name: /terminer/i }).click();
+
+			await expect(confirmDialog).not.toBeVisible({ timeout: 10000 });
+			await expect(page.getByText(/remplacement terminé/i)).toBeVisible({ timeout: 10000 });
+		});
+	});
+
+	// ============================================================================
+	// AC4: Active Replacements Display
+	// ============================================================================
+	test.describe('AC4: Active Replacements Display', () => {
+		test('shows countdown for active replacements', async ({ page }) => {
+			await loginAsAdmin(page);
+			await page.goto(`${ALPHA_URL}/admin/replacements`);
+			await waitForPageReady(page);
+
+			// Create a replacement
+			await openCreateDialog(page);
+			await page.locator('#replaced-teacher').selectOption({ index: 1 });
+			await page.locator('#replacement-teacher').selectOption({ index: 1 });
+			await page.locator('#start-date').fill(getTodayDate());
+			await page.locator('#end-date').fill(getFutureDate(10));
+			const firstClassSelect = page.locator('.class-pair-row select').first();
+			await firstClassSelect.selectOption({ index: 1 });
+			const firstSubjectSelect = page.locator('.class-pair-row select').nth(1);
+			await firstSubjectSelect.selectOption({ index: 1 });
+			await page.getByRole('button', { name: /désigner le remplaçant/i }).click();
+			await expect(page.getByRole('dialog')).not.toBeVisible({ timeout: 10000 });
+
+			// Verify countdown is displayed
+			await expect(page.locator('.countdown')).toBeVisible({ timeout: 10000 });
+			await expect(page.getByText(/jours? restants?/i)).toBeVisible();
+
+			// Verify status badge
+			await expect(page.locator('.status-active')).toBeVisible();
+		});
+	});
+});
diff --git a/frontend/src/lib/components/organisms/Dashboard/DashboardAdmin.svelte b/frontend/src/lib/components/organisms/Dashboard/DashboardAdmin.svelte
index 05345c6..876413b 100644
--- a/frontend/src/lib/components/organisms/Dashboard/DashboardAdmin.svelte
+++ b/frontend/src/lib/components/organisms/Dashboard/DashboardAdmin.svelte
@@ -46,6 +46,11 @@
 				<span class="action-label">Affectations</span>
 				<span class="action-hint">Enseignants et classes</span>
 			</a>
+			<a class="action-card" href="/admin/replacements">
+				<span class="action-icon">🔄</span>
+				<span class="action-label">Remplacements</span>
+				<span class="action-hint">Enseignants absents</span>
+			</a>
 			<a class="action-card" href="/admin/academic-year/periods">
 				<span class="action-icon">📅</span>
 				<span class="action-label">Périodes scolaires</span>
diff --git a/frontend/src/lib/components/organisms/Dashboard/DashboardTeacher.svelte b/frontend/src/lib/components/organisms/Dashboard/DashboardTeacher.svelte
index 266d246..7219034 100644
--- a/frontend/src/lib/components/organisms/Dashboard/DashboardTeacher.svelte
+++ b/frontend/src/lib/components/organisms/Dashboard/DashboardTeacher.svelte
@@ -1,6 +1,9 @@
 <script lang="ts">
 	import DashboardSection from '$lib/components/molecules/DashboardSection.svelte';
 	import SkeletonList from '$lib/components/atoms/Skeleton/SkeletonList.svelte';
+	import { getApiBaseUrl } from '$lib/api/config';
+	import { authenticatedFetch, isAuthenticated } from '$lib/auth';
+	import { untrack } from 'svelte';
 
 	let {
 		isLoading = false,
@@ -9,6 +12,53 @@
 		isLoading?: boolean;
 		hasRealData?: boolean;
 	} = $props();
+
+	interface ReplacedClass {
+		replacementId: string;
+		replacedTeacherId: string;
+		classId: string;
+		subjectId: string;
+		className: string;
+		subjectName: string;
+		startDate: string;
+		endDate: string;
+	}
+
+	let replacedClasses = $state<ReplacedClass[]>([]);
+	let replacementsLoading = $state(false);
+
+	$effect(() => {
+		untrack(() => {
+			if (isAuthenticated()) {
+				loadReplacedClasses();
+			}
+		});
+	});
+
+	async function loadReplacedClasses() {
+		try {
+			replacementsLoading = true;
+			const apiUrl = getApiBaseUrl();
+			const response = await authenticatedFetch(`${apiUrl}/me/replaced-classes`);
+
+			if (!response.ok) return;
+
+			const data = await response.json();
+			replacedClasses = Array.isArray(data) ? data : (data['hydra:member'] ?? []);
+		} catch {
+			// Silently fail - not critical for dashboard display
+		} finally {
+			replacementsLoading = false;
+		}
+	}
+
+	function daysRemaining(endDate: string): number {
+		const end = new Date(endDate);
+		const now = new Date();
+		now.setHours(0, 0, 0, 0);
+		end.setHours(0, 0, 0, 0);
+		return Math.ceil((end.getTime() - now.getTime()) / (1000 * 60 * 60 * 24));
+	}
 </script>
 
 <div class="dashboard-teacher">
@@ -35,6 +85,44 @@
 		</div>
 	</div>
 
+	{#if replacedClasses.length > 0}
+		<DashboardSection
+			title="Classes en remplacement"
+			subtitle="Vous remplacez actuellement un enseignant"
+		>
+			<div class="replacement-list">
+				{#each replacedClasses as rc}
+					{@const days = daysRemaining(rc.endDate)}
+					<div class="replacement-card">
+						<div class="replacement-badge">Remplacement</div>
+						<div class="replacement-info">
+							<span class="replacement-class">{rc.className}</span>
+							<span class="replacement-subject">{rc.subjectName}</span>
+						</div>
+						<div class="replacement-dates">
+							{new Date(rc.startDate).toLocaleDateString('fr-FR')}
+							&rarr;
+							{new Date(rc.endDate).toLocaleDateString('fr-FR')}
+							<span class="replacement-countdown" class:urgent={days <= 3}>
+								{#if days > 1}
+									({days} jours restants)
+								{:else if days === 1}
+									(1 jour restant)
+								{:else}
+									(Dernier jour)
+								{/if}
+							</span>
+						</div>
+					</div>
+				{/each}
+			</div>
+		</DashboardSection>
+	{:else if replacementsLoading}
+		<DashboardSection title="Classes en remplacement">
+			<SkeletonList items={2} message="Chargement des remplacements..." />
+		</DashboardSection>
+	{/if}
+
 	<div class="dashboard-grid">
 		<DashboardSection
 			title="Mes classes aujourd'hui"
@@ -164,6 +252,62 @@
 		grid-template-columns: 1fr;
 	}
 
+	/* Replacement section */
+	.replacement-list {
+		display: flex;
+		flex-direction: column;
+		gap: 0.75rem;
+	}
+
+	.replacement-card {
+		padding: 0.75rem 1rem;
+		background: #eff6ff;
+		border: 1px solid #bfdbfe;
+		border-radius: 0.5rem;
+	}
+
+	.replacement-badge {
+		display: inline-block;
+		padding: 0.125rem 0.5rem;
+		background: #3b82f6;
+		color: white;
+		border-radius: 9999px;
+		font-size: 0.6875rem;
+		font-weight: 600;
+		margin-bottom: 0.5rem;
+	}
+
+	.replacement-info {
+		display: flex;
+		gap: 0.5rem;
+		align-items: center;
+		margin-bottom: 0.25rem;
+	}
+
+	.replacement-class {
+		font-weight: 600;
+		color: #1f2937;
+	}
+
+	.replacement-subject {
+		color: #4b5563;
+		font-size: 0.875rem;
+	}
+
+	.replacement-dates {
+		font-size: 0.8125rem;
+		color: #6b7280;
+	}
+
+	.replacement-countdown {
+		font-weight: 500;
+		color: #16a34a;
+	}
+
+	.replacement-countdown.urgent {
+		color: #dc2626;
+	}
+
 	@media (min-width: 768px) {
 		.dashboard-grid {
 			grid-template-columns: repeat(2, 1fr);
diff --git a/frontend/src/routes/admin/+layout.svelte b/frontend/src/routes/admin/+layout.svelte
index 8eb5b9d..bae5d4d 100644
--- a/frontend/src/routes/admin/+layout.svelte
+++ b/frontend/src/routes/admin/+layout.svelte
@@ -10,6 +10,7 @@
 	let isLoggingOut = $state(false);
 	let accessChecked = $state(false);
 	let hasAccess = $state(false);
+	let mobileMenuOpen = $state(false);
 
 	const ADMIN_ROLES = [
 		'ROLE_SUPER_ADMIN',
@@ -18,6 +19,17 @@
 		'ROLE_SECRETARIAT'
 	];
 
+	const navLinks = [
+		{ href: '/dashboard', label: 'Tableau de bord', isActive: () => false },
+		{ href: '/admin/users', label: 'Utilisateurs', isActive: () => isUsersActive },
+		{ href: '/admin/classes', label: 'Classes', isActive: () => isClassesActive },
+		{ href: '/admin/subjects', label: 'Matières', isActive: () => isSubjectsActive },
+		{ href: '/admin/assignments', label: 'Affectations', isActive: () => isAssignmentsActive },
+		{ href: '/admin/replacements', label: 'Remplacements', isActive: () => isReplacementsActive },
+		{ href: '/admin/academic-year/periods', label: 'Périodes', isActive: () => isPeriodsActive },
+		{ href: '/admin/pedagogy', label: 'Pédagogie', isActive: () => isPedagogyActive }
+	];
+
 	// Load user roles and verify admin access
 	onMount(async () => {
 		await fetchRoles();
@@ -51,13 +63,65 @@
 		goto('/settings');
 	}
 
+	function toggleMobileMenu() {
+		mobileMenuOpen = !mobileMenuOpen;
+	}
+
+	function closeMobileMenu() {
+		mobileMenuOpen = false;
+	}
+
 	// Determine which admin section is active
 	const isUsersActive = $derived(page.url.pathname.startsWith('/admin/users'));
 	const isClassesActive = $derived(page.url.pathname.startsWith('/admin/classes'));
 	const isSubjectsActive = $derived(page.url.pathname.startsWith('/admin/subjects'));
 	const isPeriodsActive = $derived(page.url.pathname.startsWith('/admin/academic-year/periods'));
 	const isAssignmentsActive = $derived(page.url.pathname.startsWith('/admin/assignments'));
+	const isReplacementsActive = $derived(page.url.pathname.startsWith('/admin/replacements'));
 	const isPedagogyActive = $derived(page.url.pathname.startsWith('/admin/pedagogy'));
+
+	const currentSectionLabel = $derived.by(() => {
+		const path = page.url.pathname;
+		for (const link of navLinks) {
+			if (link.href !== '/dashboard' && path.startsWith(link.href)) {
+				return link.label;
+			}
+		}
+		return 'Administration';
+	});
+
+	// Close menu on route change
+	$effect(() => {
+		void page.url.pathname;
+		mobileMenuOpen = false;
+	});
+
+	// Close menu on Escape key
+	$effect(() => {
+		if (!mobileMenuOpen) return;
+
+		function handleKeydown(e: KeyboardEvent) {
+			if (e.key === 'Escape') {
+				mobileMenuOpen = false;
+			}
+		}
+
+		document.addEventListener('keydown', handleKeydown);
+		return () => document.removeEventListener('keydown', handleKeydown);
+	});
+
+	// Lock body scroll when menu is open
+	$effect(() => {
+		if (mobileMenuOpen) {
+			document.body.style.overflow = 'hidden';
+		} else {
+			document.body.style.overflow = '';
+		}
+
+		return () => {
+			document.body.style.overflow = '';
+		};
+	});
 </script>
 
 {#if !accessChecked}
@@ -71,15 +135,25 @@
 				<button class="logo-button" onclick={goHome}>
 					<span class="logo-text">Classeo</span>
 				</button>
-				<nav class="header-nav">
+
+				<span class="mobile-section-label">{currentSectionLabel}</span>
+
+				<button
+					class="hamburger-button"
+					onclick={toggleMobileMenu}
+					aria-expanded={mobileMenuOpen}
+					aria-label="Ouvrir le menu de navigation"
+				>
+					<span class="hamburger-line"></span>
+					<span class="hamburger-line"></span>
+					<span class="hamburger-line"></span>
+				</button>
+
+				<nav class="desktop-nav">
 					<RoleSwitcher />
-					<a href="/dashboard" class="nav-link">Tableau de bord</a>
-					<a href="/admin/users" class="nav-link" class:active={isUsersActive}>Utilisateurs</a>
-					<a href="/admin/classes" class="nav-link" class:active={isClassesActive}>Classes</a>
-					<a href="/admin/subjects" class="nav-link" class:active={isSubjectsActive}>Matières</a>
-					<a href="/admin/assignments" class="nav-link" class:active={isAssignmentsActive}>Affectations</a>
-					<a href="/admin/academic-year/periods" class="nav-link" class:active={isPeriodsActive}>Périodes</a>
-					<a href="/admin/pedagogy" class="nav-link" class:active={isPedagogyActive}>Pédagogie</a>
+					{#each navLinks as link}
+						<a href={link.href} class="nav-link" class:active={link.isActive()}>{link.label}</a>
+					{/each}
 					<button class="nav-button" onclick={goSettings}>Paramètres</button>
 					<button class="logout-button" onclick={handleLogout} disabled={isLoggingOut}>
 						{#if isLoggingOut}
@@ -93,6 +167,60 @@
 			</div>
 		</header>
 
+		{#if mobileMenuOpen}
+			<div
+				class="mobile-overlay"
+				onclick={closeMobileMenu}
+				onkeydown={(e) => e.key === 'Enter' && closeMobileMenu()}
+				role="presentation"
+			></div>
+			<div
+				class="mobile-drawer"
+				role="dialog"
+				aria-modal="true"
+				aria-label="Menu de navigation"
+			>
+				<div class="mobile-drawer-header">
+					<span class="logo-text">Classeo</span>
+					<button
+						class="mobile-close"
+						onclick={closeMobileMenu}
+						aria-label="Fermer le menu"
+					>
+						&times;
+					</button>
+				</div>
+				<div class="mobile-drawer-body">
+					<div class="mobile-role-switcher">
+						<RoleSwitcher />
+					</div>
+					{#each navLinks as link}
+						<a
+							href={link.href}
+							class="mobile-nav-link"
+							class:active={link.isActive()}
+						>
+							{link.label}
+						</a>
+					{/each}
+				</div>
+				<div class="mobile-drawer-footer">
+					<button class="mobile-nav-link" onclick={goSettings}>Paramètres</button>
+					<button
+						class="mobile-nav-link mobile-logout"
+						onclick={handleLogout}
+						disabled={isLoggingOut}
+					>
+						{#if isLoggingOut}
+							Déconnexion...
+						{:else}
+							Déconnexion
+						{/if}
+					</button>
+				</div>
+			</div>
+		{/if}
+
 		<main class="admin-main">
 			<div class="main-content">
 				{@render children()}
@@ -131,9 +259,8 @@
 		display: flex;
 		justify-content: space-between;
 		align-items: center;
-		flex-wrap: wrap;
-		height: auto;
-		padding: 0.75rem 0;
+		height: 56px;
+		padding: 0;
 		gap: 0.75rem;
 	}
 
@@ -150,23 +277,64 @@
 		color: var(--accent-primary, #0ea5e9);
 	}
 
-	.header-nav {
+	/* Mobile section label */
+	.mobile-section-label {
+		font-size: 0.875rem;
+		font-weight: 600;
+		color: var(--text-primary, #1f2937);
+		flex: 1;
+		text-align: center;
+		overflow: hidden;
+		text-overflow: ellipsis;
+		white-space: nowrap;
+	}
+
+	/* Hamburger button */
+	.hamburger-button {
 		display: flex;
+		flex-direction: column;
+		justify-content: center;
 		align-items: center;
-		width: 100%;
-		justify-content: flex-end;
-		flex-wrap: wrap;
-		gap: 0.5rem;
+		gap: 5px;
+		width: 40px;
+		height: 40px;
+		background: none;
+		border: none;
+		cursor: pointer;
+		padding: 8px;
+		border-radius: 0.5rem;
+		flex-shrink: 0;
+	}
+
+	.hamburger-button:hover {
+		background: var(--surface-primary, #f8fafc);
+	}
+
+	.hamburger-line {
+		display: block;
+		width: 20px;
+		height: 2px;
+		background: var(--text-secondary, #64748b);
+		border-radius: 1px;
+	}
+
+	/* Desktop nav — hidden on mobile */
+	.desktop-nav {
+		display: none;
+		align-items: center;
+		gap: 0.125rem;
 	}
 
 	.nav-link {
-		padding: 0.5rem 1rem;
-		font-size: 0.875rem;
+		padding: 0.375rem 0.625rem;
+		font-size: 0.8125rem;
 		font-weight: 500;
 		color: var(--text-secondary, #64748b);
 		text-decoration: none;
 		border-radius: 0.5rem;
 		transition: all 0.2s;
+		white-space: nowrap;
+		flex-shrink: 0;
 	}
 
 	.nav-link:hover {
@@ -180,8 +348,8 @@
 	}
 
 	.nav-button {
-		padding: 0.5rem 1rem;
-		font-size: 0.875rem;
+		padding: 0.375rem 0.625rem;
+		font-size: 0.8125rem;
 		font-weight: 500;
 		color: var(--text-secondary, #64748b);
 		background: transparent;
@@ -189,6 +357,8 @@
 		border-radius: 0.5rem;
 		cursor: pointer;
 		transition: all 0.2s;
+		white-space: nowrap;
+		flex-shrink: 0;
 	}
 
 	.nav-button:hover {
@@ -199,9 +369,9 @@
 	.logout-button {
 		display: inline-flex;
 		align-items: center;
-		gap: 0.5rem;
-		padding: 0.5rem 1rem;
-		font-size: 0.875rem;
+		gap: 0.375rem;
+		padding: 0.375rem 0.625rem;
+		font-size: 0.8125rem;
 		font-weight: 500;
 		color: var(--text-secondary, #64748b);
 		background: transparent;
@@ -209,6 +379,8 @@
 		border-radius: 0.5rem;
 		cursor: pointer;
 		transition: all 0.2s;
+		white-space: nowrap;
+		flex-shrink: 0;
 	}
 
 	.logout-button:hover:not(:disabled) {
@@ -221,6 +393,118 @@
 		cursor: not-allowed;
 	}
 
+	/* Mobile overlay */
+	.mobile-overlay {
+		position: fixed;
+		inset: 0;
+		background: rgba(0, 0, 0, 0.4);
+		z-index: 200;
+		animation: fadeIn 0.2s ease-out;
+	}
+
+	/* Mobile drawer */
+	.mobile-drawer {
+		position: fixed;
+		top: 0;
+		left: 0;
+		bottom: 0;
+		width: min(320px, 85vw);
+		background: var(--surface-elevated, #fff);
+		z-index: 201;
+		display: flex;
+		flex-direction: column;
+		animation: slideInLeft 0.25s ease-out;
+	}
+
+	.mobile-drawer-header {
+		display: flex;
+		align-items: center;
+		justify-content: space-between;
+		padding: 1rem 1.25rem;
+		border-bottom: 1px solid var(--border-subtle, #e2e8f0);
+	}
+
+	.mobile-close {
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		width: 36px;
+		height: 36px;
+		background: none;
+		border: none;
+		cursor: pointer;
+		font-size: 1.5rem;
+		color: var(--text-secondary, #64748b);
+		border-radius: 0.5rem;
+	}
+
+	.mobile-close:hover {
+		background: var(--surface-primary, #f8fafc);
+		color: var(--text-primary, #1f2937);
+	}
+
+	.mobile-drawer-body {
+		flex: 1;
+		overflow-y: auto;
+		padding: 0.75rem 0;
+	}
+
+	.mobile-role-switcher {
+		padding: 0.5rem 1.25rem 0.75rem;
+		border-bottom: 1px solid var(--border-subtle, #e2e8f0);
+		margin-bottom: 0.5rem;
+	}
+
+	.mobile-nav-link {
+		display: flex;
+		align-items: center;
+		width: 100%;
+		padding: 0.75rem 1.25rem;
+		font-size: 0.9375rem;
+		font-weight: 500;
+		color: var(--text-secondary, #64748b);
+		text-decoration: none;
+		border: none;
+		background: none;
+		cursor: pointer;
+		border-left: 3px solid transparent;
+		transition: all 0.15s;
+	}
+
+	.mobile-nav-link:hover {
+		background: var(--surface-primary, #f8fafc);
+		color: var(--text-primary, #1f2937);
+	}
+
+	.mobile-nav-link.active {
+		color: var(--accent-primary, #0ea5e9);
+		border-left-color: var(--accent-primary, #0ea5e9);
+		background: var(--accent-primary-light, #e0f2fe);
+	}
+
+	.mobile-logout {
+		color: var(--color-alert, #ef4444);
+	}
+
+	.mobile-logout:hover {
+		background: #fef2f2;
+	}
+
+	.mobile-drawer-footer {
+		border-top: 1px solid var(--border-subtle, #e2e8f0);
+		padding: 0.5rem 0;
+	}
+
+	@keyframes fadeIn {
+		from { opacity: 0; }
+		to { opacity: 1; }
+	}
+
+	@keyframes slideInLeft {
+		from { transform: translateX(-100%); }
+		to { transform: translateX(0); }
+	}
+
 	.spinner {
 		width: 14px;
 		height: 14px;
@@ -246,18 +530,33 @@
 		}
 	}
 
-	@media (min-width: 768px) {
+	@media (min-width: 1200px) {
 		.header-content {
-			flex-wrap: nowrap;
 			height: 64px;
-			padding: 0;
 			gap: 0;
 		}
 
-		.header-nav {
-			width: auto;
-			flex-wrap: nowrap;
-			justify-content: flex-start;
+		.mobile-section-label {
+			display: none;
+		}
+
+		.hamburger-button {
+			display: none;
+		}
+
+		.desktop-nav {
+			display: flex;
+		}
+
+		.nav-link,
+		.nav-button {
+			padding: 0.5rem 0.75rem;
+			font-size: 0.875rem;
+		}
+
+		.logout-button {
+			padding: 0.5rem 0.75rem;
+			font-size: 0.875rem;
 		}
 
 		.admin-main {
diff --git a/frontend/src/routes/admin/+page.svelte b/frontend/src/routes/admin/+page.svelte
deleted file mode 100644
index 51eda47..0000000
--- a/frontend/src/routes/admin/+page.svelte
+++ /dev/null
@@ -1,173 +0,0 @@
-<script lang="ts">
-	import { getApiBaseUrl } from '$lib/api/config';
-	import { authenticatedFetch } from '$lib/auth/auth.svelte';
-
-	let classCount = $state<number | null>(null);
-	let subjectCount = $state<number | null>(null);
-
-	$effect(() => {
-		loadStats();
-	});
-
-	async function loadStats() {
-		const base = getApiBaseUrl();
-
-		const [classesRes, subjectsRes] = await Promise.allSettled([
-			authenticatedFetch(`${base}/classes`),
-			authenticatedFetch(`${base}/subjects`)
-		]);
-
-		if (classesRes.status === 'fulfilled' && classesRes.value.ok) {
-			const data = await classesRes.value.json();
-			classCount = Array.isArray(data) ? data.length : (data['hydra:totalItems'] ?? null);
-		}
-
-		if (subjectsRes.status === 'fulfilled' && subjectsRes.value.ok) {
-			const data = await subjectsRes.value.json();
-			subjectCount = Array.isArray(data) ? data.length : (data['hydra:totalItems'] ?? null);
-		}
-	}
-</script>
-
-<svelte:head>
-	<title>Administration - Classeo</title>
-</svelte:head>
-
-<div class="admin-dashboard">
-	<header class="page-header">
-		<h1>Administration</h1>
-		<p class="subtitle">Configurez votre établissement</p>
-	</header>
-
-	<div class="stats-row">
-		<div class="stat-card">
-			<span class="stat-value">{classCount ?? '–'}</span>
-			<span class="stat-label">Classes</span>
-		</div>
-		<div class="stat-card">
-			<span class="stat-value">{subjectCount ?? '–'}</span>
-			<span class="stat-label">Matières</span>
-		</div>
-	</div>
-
-	<div class="action-cards">
-		<a class="action-card" href="/admin/classes">
-			<span class="action-icon">🏫</span>
-			<span class="action-label">Classes</span>
-			<span class="action-hint">Créer et gérer les classes</span>
-		</a>
-		<a class="action-card" href="/admin/subjects">
-			<span class="action-icon">📚</span>
-			<span class="action-label">Matières</span>
-			<span class="action-hint">Créer et gérer les matières</span>
-		</a>
-		<a class="action-card" href="/admin/academic-year/periods">
-			<span class="action-icon">📅</span>
-			<span class="action-label">Périodes scolaires</span>
-			<span class="action-hint">Trimestres ou semestres</span>
-		</a>
-	</div>
-</div>
-
-<style>
-	.admin-dashboard {
-		display: flex;
-		flex-direction: column;
-		gap: 1.5rem;
-	}
-
-	.page-header h1 {
-		margin: 0;
-		font-size: 1.5rem;
-		font-weight: 700;
-		color: var(--text-primary, #1f2937);
-	}
-
-	.subtitle {
-		margin: 0.25rem 0 0;
-		color: var(--text-secondary, #64748b);
-		font-size: 0.875rem;
-	}
-
-	.stats-row {
-		display: flex;
-		flex-wrap: wrap;
-		gap: 1rem;
-	}
-
-	.stat-card {
-		display: flex;
-		flex-direction: column;
-		align-items: center;
-		gap: 0.25rem;
-		padding: 1rem 1.5rem;
-		background: var(--surface-elevated, #fff);
-		border: 1px solid var(--border-subtle, #e2e8f0);
-		border-radius: 0.75rem;
-		min-width: 100px;
-		flex: 1;
-	}
-
-	.stat-value {
-		font-size: 1.5rem;
-		font-weight: 700;
-		color: var(--text-primary, #1f2937);
-	}
-
-	.stat-label {
-		font-size: 0.75rem;
-		color: var(--text-secondary, #64748b);
-	}
-
-	.action-cards {
-		display: grid;
-		grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
-		gap: 1rem;
-	}
-
-	.action-card {
-		display: flex;
-		flex-direction: column;
-		align-items: center;
-		gap: 0.5rem;
-		padding: 1.5rem 1rem;
-		background: var(--surface-elevated, #fff);
-		border: 2px solid var(--border-subtle, #e2e8f0);
-		border-radius: 0.75rem;
-		text-decoration: none;
-		color: inherit;
-		transition: all 0.2s;
-	}
-
-	.action-card:hover {
-		border-color: var(--accent-primary, #0ea5e9);
-		background: var(--accent-primary-light, #e0f2fe);
-		transform: translateY(-2px);
-		box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
-	}
-
-	.action-icon {
-		font-size: 2rem;
-	}
-
-	.action-label {
-		font-weight: 600;
-		color: var(--text-primary, #374151);
-	}
-
-	.action-hint {
-		font-size: 0.75rem;
-		color: var(--text-secondary, #6b7280);
-		text-align: center;
-	}
-
-	@media (min-width: 640px) {
-		.stats-row {
-			flex-wrap: nowrap;
-		}
-
-		.stat-card {
-			flex: 0 1 auto;
-		}
-	}
-</style>
diff --git a/frontend/src/routes/admin/+page.ts b/frontend/src/routes/admin/+page.ts
new file mode 100644
index 0000000..4f0ddad
--- /dev/null
+++ b/frontend/src/routes/admin/+page.ts
@@ -0,0 +1,5 @@
+import { redirect } from '@sveltejs/kit';
+
+export function load() {
+	redirect(302, '/admin/users');
+}
diff --git a/frontend/src/routes/admin/assignments/+page.svelte b/frontend/src/routes/admin/assignments/+page.svelte
index 378f6f5..93ae729 100644
--- a/frontend/src/routes/admin/assignments/+page.svelte
+++ b/frontend/src/routes/admin/assignments/+page.svelte
@@ -352,11 +352,11 @@
 				<tbody>
 					{#each assignments as assignment (assignment.id)}
 						<tr>
-							<td class="teacher-cell">
+							<td data-label="Enseignant" class="teacher-cell">
 								<span class="teacher-name">{assignment.teacherFirstName} {assignment.teacherLastName}</span>
 							</td>
-							<td>{assignment.className}</td>
-							<td>
+							<td data-label="Classe">{assignment.className}</td>
+							<td data-label="Matière">
 								{#if getSubjectColor(assignment.subjectId)}
 									<span
 										class="subject-badge"
@@ -368,13 +368,13 @@
 									{assignment.subjectName}
 								{/if}
 							</td>
-							<td>
+							<td data-label="Statut">
 								<span class="status-badge status-active">Active</span>
 							</td>
-							<td class="date-cell">
+							<td data-label="Depuis le" class="date-cell">
 								{new Date(assignment.startDate).toLocaleDateString('fr-FR')}
 							</td>
-							<td class="actions-cell">
+							<td data-label="Actions" class="actions-cell">
 								<button
 									class="btn-remove"
 									onclick={() => openDeleteModal(assignment)}
@@ -916,12 +916,58 @@
 		color: #6b7280;
 	}
 
-	@media (min-width: 768px) {
-		.assignments-table th:nth-child(4),
-		.assignments-table td:nth-child(4),
-		.assignments-table th:nth-child(5),
-		.assignments-table td:nth-child(5) {
-			display: table-cell;
+	@media (max-width: 767px) {
+		.table-container {
+			background: transparent;
+			border: none;
+		}
+
+		.assignments-table thead {
+			display: none;
+		}
+
+		.assignments-table tbody tr {
+			display: block;
+			background: white;
+			border: 1px solid #e5e7eb;
+			border-radius: 0.75rem;
+			margin-bottom: 0.75rem;
+			padding: 0.25rem 0;
+		}
+
+		.assignments-table tr:hover td {
+			background: transparent;
+		}
+
+		.assignments-table td {
+			display: flex;
+			justify-content: space-between;
+			align-items: baseline;
+			padding: 0.5rem 1rem;
+			border-bottom: none;
+			text-align: right;
+		}
+
+		.assignments-table td::before {
+			content: attr(data-label);
+			font-weight: 600;
+			font-size: 0.75rem;
+			color: #6b7280;
+			text-transform: uppercase;
+			letter-spacing: 0.05em;
+			text-align: left;
+			margin-right: 1rem;
+			flex-shrink: 0;
+		}
+
+		.teacher-cell {
+			white-space: normal;
+		}
+
+		.actions-cell {
+			justify-content: flex-end;
+			padding-top: 0.75rem;
+			border-top: 1px solid #f3f4f6;
 		}
 	}
 </style>
diff --git a/frontend/src/routes/admin/replacements/+page.svelte b/frontend/src/routes/admin/replacements/+page.svelte
new file mode 100644
index 0000000..527d14f
--- /dev/null
+++ b/frontend/src/routes/admin/replacements/+page.svelte
@@ -0,0 +1,1268 @@
+<script lang="ts">
+	import { goto } from '$app/navigation';
+	import { page } from '$app/state';
+	import { getApiBaseUrl } from '$lib/api/config';
+	import { authenticatedFetch } from '$lib/auth';
+	import Pagination from '$lib/components/molecules/Pagination/Pagination.svelte';
+	import SearchInput from '$lib/components/molecules/SearchInput/SearchInput.svelte';
+	import { untrack } from 'svelte';
+
+	// Types
+	interface TeacherReplacement {
+		id: string;
+		replacedTeacherId: string;
+		replacementTeacherId: string;
+		startDate: string;
+		endDate: string;
+		status: string;
+		classes: Array<{ classId: string; subjectId: string }>;
+		reason: string | null;
+		createdAt: string | null;
+		endedAt: string | null;
+	}
+
+	interface User {
+		id: string;
+		firstName: string;
+		lastName: string;
+		email: string;
+		roles: string[];
+	}
+
+	interface SchoolClass {
+		id: string;
+		name: string;
+		level: string | null;
+		status: string;
+	}
+
+	interface Subject {
+		id: string;
+		name: string;
+		code: string;
+		color: string | null;
+		status: string;
+	}
+
+	interface ClassSubjectPair {
+		classId: string;
+		subjectId: string;
+	}
+
+	// State
+	let replacements = $state<TeacherReplacement[]>([]);
+	let teachers = $state<User[]>([]);
+	let classes = $state<SchoolClass[]>([]);
+	let subjects = $state<Subject[]>([]);
+	let isLoading = $state(true);
+	let error = $state<string | null>(null);
+	let successMessage = $state<string | null>(null);
+
+	// Pagination & Search
+	let currentPage = $state(Number(page.url.searchParams.get('page')) || 1);
+	let searchTerm = $state(page.url.searchParams.get('search') ?? '');
+	let totalItems = $state(0);
+	const itemsPerPage = 30;
+	let totalPages = $derived(Math.ceil(totalItems / itemsPerPage));
+
+	// Create modal
+	let showCreateModal = $state(false);
+	let selectedReplacedTeacherId = $state('');
+	let selectedReplacementTeacherId = $state('');
+	let selectedStartDate = $state('');
+	let selectedEndDate = $state('');
+	let selectedReason = $state('');
+	let classPairs = $state<ClassSubjectPair[]>([{ classId: '', subjectId: '' }]);
+	let isSubmitting = $state(false);
+
+	// Delete (end) state
+	let showEndModal = $state(false);
+	let replacementToEnd = $state<TeacherReplacement | null>(null);
+	let isEnding = $state(false);
+
+	// Validation
+	let isFormValid = $derived(
+		selectedReplacedTeacherId !== '' &&
+			selectedReplacementTeacherId !== '' &&
+			selectedReplacedTeacherId !== selectedReplacementTeacherId &&
+			selectedStartDate !== '' &&
+			selectedEndDate !== '' &&
+			selectedEndDate >= selectedStartDate &&
+			classPairs.some((p) => p.classId !== '' && p.subjectId !== '')
+	);
+
+	// Load everything on mount
+	$effect(() => {
+		untrack(() => loadAll());
+	});
+
+	async function loadAll() {
+		try {
+			isLoading = true;
+			error = null;
+			const apiUrl = getApiBaseUrl();
+
+			const [teachersRes, classesRes, subjectsRes] = await Promise.all([
+				authenticatedFetch(`${apiUrl}/users?role=ROLE_PROF&itemsPerPage=100`),
+				authenticatedFetch(`${apiUrl}/classes?itemsPerPage=100`),
+				authenticatedFetch(`${apiUrl}/subjects?itemsPerPage=100`)
+			]);
+
+			if (!teachersRes.ok) throw new Error('Erreur lors du chargement des enseignants');
+			if (!classesRes.ok) throw new Error('Erreur lors du chargement des classes');
+			if (!subjectsRes.ok) throw new Error('Erreur lors du chargement des matières');
+
+			const [teachersData, classesData, subjectsData] = await Promise.all([
+				teachersRes.json(),
+				classesRes.json(),
+				subjectsRes.json()
+			]);
+
+			teachers = extractCollection(teachersData);
+			classes = extractCollection(classesData);
+			subjects = extractCollection(subjectsData);
+
+			await loadReplacements();
+		} catch (e) {
+			error = e instanceof Error ? e.message : 'Erreur inconnue';
+		} finally {
+			isLoading = false;
+		}
+	}
+
+	let replacementsAbortController: AbortController | null = null;
+
+	async function loadReplacements() {
+		replacementsAbortController?.abort();
+		const controller = new AbortController();
+		replacementsAbortController = controller;
+
+		const apiUrl = getApiBaseUrl();
+		const params = new URLSearchParams();
+		params.set('page', String(currentPage));
+		params.set('itemsPerPage', String(itemsPerPage));
+		if (searchTerm) params.set('search', searchTerm);
+		const response = await authenticatedFetch(
+			`${apiUrl}/teacher-replacements?${params.toString()}`,
+			{ signal: controller.signal }
+		);
+
+		if (controller.signal.aborted) return;
+
+		if (!response.ok) {
+			throw new Error('Erreur lors du chargement des remplacements');
+		}
+
+		const data = await response.json();
+		replacements = data['hydra:member'] ?? data['member'] ?? [];
+		totalItems = data['hydra:totalItems'] ?? data['totalItems'] ?? replacements.length;
+	}
+
+	function extractCollection<T>(data: Record<string, unknown>): T[] {
+		const hydra = data['hydra:member'];
+		if (Array.isArray(hydra)) return hydra as T[];
+		const member = data['member'];
+		if (Array.isArray(member)) return member as T[];
+		if (Array.isArray(data)) return data as T[];
+		return [];
+	}
+
+	function getTeacherName(teacherId: string): string {
+		const teacher = teachers.find((t) => t.id === teacherId);
+		return teacher ? `${teacher.firstName} ${teacher.lastName}` : teacherId;
+	}
+
+	function getClassName(classId: string): string {
+		const cls = classes.find((c) => c.id === classId);
+		return cls?.name ?? classId;
+	}
+
+	function getSubjectName(subjectId: string): string {
+		const subject = subjects.find((s) => s.id === subjectId);
+		return subject?.name ?? subjectId;
+	}
+
+	function getSubjectColor(subjectId: string): string | null {
+		const subject = subjects.find((s) => s.id === subjectId);
+		return subject?.color ?? null;
+	}
+
+	function daysRemaining(endDate: string): number {
+		const end = new Date(endDate);
+		const now = new Date();
+		now.setHours(0, 0, 0, 0);
+		end.setHours(0, 0, 0, 0);
+		return Math.ceil((end.getTime() - now.getTime()) / (1000 * 60 * 60 * 24));
+	}
+
+	function updateUrl() {
+		const params = new URLSearchParams();
+		if (currentPage > 1) params.set('page', String(currentPage));
+		if (searchTerm) params.set('search', searchTerm);
+		const query = params.toString();
+		goto(`?${query}`, { replaceState: true, noScroll: true, keepFocus: true });
+	}
+
+	function handleSearch(value: string) {
+		searchTerm = value;
+		currentPage = 1;
+		updateUrl();
+		reloadReplacements();
+	}
+
+	function handlePageChange(newPage: number) {
+		currentPage = newPage;
+		updateUrl();
+		reloadReplacements();
+	}
+
+	async function reloadReplacements() {
+		try {
+			isLoading = true;
+			error = null;
+			await loadReplacements();
+		} catch (e) {
+			error = e instanceof Error ? e.message : 'Erreur inconnue';
+		} finally {
+			isLoading = false;
+		}
+	}
+
+	function openCreateModal() {
+		showCreateModal = true;
+		selectedReplacedTeacherId = '';
+		selectedReplacementTeacherId = '';
+		selectedStartDate = '';
+		selectedEndDate = '';
+		selectedReason = '';
+		classPairs = [{ classId: '', subjectId: '' }];
+		error = null;
+	}
+
+	function closeCreateModal() {
+		showCreateModal = false;
+	}
+
+	function addClassPair() {
+		classPairs = [...classPairs, { classId: '', subjectId: '' }];
+	}
+
+	function removeClassPair(index: number) {
+		classPairs = classPairs.filter((_, i) => i !== index);
+	}
+
+	async function handleCreate() {
+		if (!isFormValid) return;
+
+		const validPairs = classPairs.filter((p) => p.classId !== '' && p.subjectId !== '');
+
+		try {
+			isSubmitting = true;
+			error = null;
+			const apiUrl = getApiBaseUrl();
+
+			const response = await authenticatedFetch(`${apiUrl}/teacher-replacements`, {
+				method: 'POST',
+				headers: { 'Content-Type': 'application/json' },
+				body: JSON.stringify({
+					replacedTeacherId: selectedReplacedTeacherId,
+					replacementTeacherId: selectedReplacementTeacherId,
+					startDate: selectedStartDate,
+					endDate: selectedEndDate,
+					classes: validPairs,
+					reason: selectedReason || null
+				})
+			});
+
+			if (!response.ok) {
+				const data = await response.json().catch(() => null);
+				const message =
+					data?.['hydra:description'] ??
+					data?.message ??
+					data?.detail ??
+					`Erreur (${response.status})`;
+				throw new Error(message);
+			}
+
+			successMessage = 'Remplacement créé avec succès';
+			closeCreateModal();
+			await reloadReplacements();
+			globalThis.setTimeout(() => {
+				successMessage = null;
+			}, 3000);
+		} catch (e) {
+			error = e instanceof Error ? e.message : 'Erreur lors de la création';
+		} finally {
+			isSubmitting = false;
+		}
+	}
+
+	function openEndModal(replacement: TeacherReplacement) {
+		replacementToEnd = replacement;
+		showEndModal = true;
+	}
+
+	function closeEndModal() {
+		showEndModal = false;
+		replacementToEnd = null;
+	}
+
+	async function handleEnd() {
+		if (!replacementToEnd) return;
+
+		try {
+			isEnding = true;
+			error = null;
+			const apiUrl = getApiBaseUrl();
+
+			const response = await authenticatedFetch(
+				`${apiUrl}/teacher-replacements/${replacementToEnd.id}`,
+				{ method: 'DELETE' }
+			);
+
+			if (!response.ok && response.status !== 204) {
+				const data = await response.json().catch(() => null);
+				const message =
+					data?.['hydra:description'] ??
+					data?.message ??
+					data?.detail ??
+					`Erreur (${response.status})`;
+				throw new Error(message);
+			}
+
+			successMessage = 'Remplacement terminé avec succès';
+			closeEndModal();
+			await reloadReplacements();
+			globalThis.setTimeout(() => {
+				successMessage = null;
+			}, 3000);
+		} catch (e) {
+			error = e instanceof Error ? e.message : 'Erreur lors de la terminaison';
+		} finally {
+			isEnding = false;
+		}
+	}
+</script>
+
+<svelte:head>
+	<title>Remplacements enseignants - Classeo</title>
+</svelte:head>
+
+<div class="replacements-page">
+	<header class="page-header">
+		<div class="header-content">
+			<h1>Remplacements enseignants</h1>
+			<p class="subtitle">Désignez des remplaçants pour les enseignants absents</p>
+		</div>
+		<button class="btn-primary" onclick={openCreateModal}>
+			<span class="btn-icon">+</span>
+			Nouveau remplacement
+		</button>
+	</header>
+
+	{#if error}
+		<div class="alert alert-error">
+			<span class="alert-icon">!</span>
+			{error}
+			<button class="alert-close" onclick={() => (error = null)}>x</button>
+		</div>
+	{/if}
+
+	{#if successMessage}
+		<div class="alert alert-success">
+			{successMessage}
+		</div>
+	{/if}
+
+	<SearchInput
+		value={searchTerm}
+		onSearch={handleSearch}
+		placeholder="Rechercher par enseignant..."
+	/>
+
+	{#if isLoading}
+		<div class="loading-state" aria-live="polite" role="status">
+			<div class="spinner"></div>
+			<p>Chargement des remplacements...</p>
+		</div>
+	{:else if replacements.length === 0}
+		<div class="empty-state">
+			<span class="empty-icon">&#x1F504;</span>
+			{#if searchTerm}
+				<h2>Aucun résultat</h2>
+				<p>Aucun remplacement ne correspond à votre recherche</p>
+				<button class="btn-secondary" onclick={() => handleSearch('')}>Effacer la recherche</button>
+			{:else}
+				<h2>Aucun remplacement actif</h2>
+				<p>Désignez un remplaçant pour un enseignant absent</p>
+				<button class="btn-primary" onclick={openCreateModal}>Nouveau remplacement</button>
+			{/if}
+		</div>
+	{:else}
+		<div class="table-container">
+			<table class="replacements-table">
+				<thead>
+					<tr>
+						<th>Enseignant remplacé</th>
+						<th>Remplaçant</th>
+						<th>Classes / Matières</th>
+						<th>Période</th>
+						<th>Statut</th>
+						<th>Actions</th>
+					</tr>
+				</thead>
+				<tbody>
+					{#each replacements as replacement (replacement.id)}
+						{@const days = daysRemaining(replacement.endDate)}
+						<tr>
+							<td data-label="Remplacé" class="teacher-cell">
+								<span class="teacher-name">{getTeacherName(replacement.replacedTeacherId)}</span>
+							</td>
+							<td data-label="Remplaçant" class="teacher-cell">
+								<span class="teacher-name">{getTeacherName(replacement.replacementTeacherId)}</span>
+							</td>
+							<td data-label="Classes / Matières" class="classes-cell">
+								{#each replacement.classes as pair}
+									{@const color = getSubjectColor(pair.subjectId)}
+									<span class="class-pair">
+										<span class="class-name">{getClassName(pair.classId)}</span>
+										{#if color}
+											<span
+												class="subject-badge"
+												style="background-color: {color}; color: white"
+											>
+												{getSubjectName(pair.subjectId)}
+											</span>
+										{:else}
+											<span class="subject-badge subject-badge-default">
+												{getSubjectName(pair.subjectId)}
+											</span>
+										{/if}
+									</span>
+								{/each}
+							</td>
+							<td data-label="Période" class="date-cell">
+								<div class="date-range">
+									{new Date(replacement.startDate).toLocaleDateString('fr-FR')}
+									&rarr;
+									{new Date(replacement.endDate).toLocaleDateString('fr-FR')}
+								</div>
+								{#if replacement.status === 'active'}
+									<span
+										class="countdown"
+										class:countdown-warning={days <= 3}
+										class:countdown-urgent={days <= 1}
+									>
+										{#if days > 1}
+											{days} jours restants
+										{:else if days === 1}
+											1 jour restant
+										{:else if days === 0}
+											Dernier jour
+										{:else}
+											Expiré
+										{/if}
+									</span>
+								{/if}
+							</td>
+							<td data-label="Statut">
+								{#if replacement.status === 'active'}
+									<span class="status-badge status-active">Actif</span>
+								{:else}
+									<span class="status-badge status-ended">Terminé</span>
+								{/if}
+							</td>
+							<td data-label="Actions" class="actions-cell">
+								{#if replacement.status === 'active'}
+									<button
+										class="btn-remove"
+										onclick={() => openEndModal(replacement)}
+									>
+										Terminer
+									</button>
+								{/if}
+							</td>
+						</tr>
+					{/each}
+				</tbody>
+			</table>
+		</div>
+		<Pagination {currentPage} {totalPages} onPageChange={handlePageChange} />
+	{/if}
+</div>
+
+<!-- Create Modal -->
+{#if showCreateModal}
+	<!-- svelte-ignore a11y_no_static_element_interactions -->
+	<div class="modal-overlay" onclick={closeCreateModal} role="presentation">
+		<div
+			class="modal modal-large"
+			role="dialog"
+			aria-modal="true"
+			aria-labelledby="create-modal-title"
+			tabindex="-1"
+			onclick={(e) => e.stopPropagation()}
+			onkeydown={(e) => { if (e.key === 'Escape') closeCreateModal(); }}
+		>
+			<header class="modal-header">
+				<h2 id="create-modal-title">Nouveau remplacement</h2>
+				<button class="modal-close" onclick={closeCreateModal} aria-label="Fermer">x</button>
+			</header>
+
+			<form
+				class="modal-body"
+				onsubmit={(e) => {
+					e.preventDefault();
+					handleCreate();
+				}}
+			>
+				<div class="form-row">
+					<div class="form-group">
+						<label for="replaced-teacher">Enseignant remplacé *</label>
+						<select id="replaced-teacher" bind:value={selectedReplacedTeacherId} required>
+							<option value="">-- Sélectionner --</option>
+							{#each teachers as teacher (teacher.id)}
+								{#if teacher.id !== selectedReplacementTeacherId}
+									<option value={teacher.id}>{teacher.firstName} {teacher.lastName}</option>
+								{/if}
+							{/each}
+						</select>
+					</div>
+
+					<div class="form-group">
+						<label for="replacement-teacher">Remplaçant *</label>
+						<select id="replacement-teacher" bind:value={selectedReplacementTeacherId} required>
+							<option value="">-- Sélectionner --</option>
+							{#each teachers as teacher (teacher.id)}
+								{#if teacher.id !== selectedReplacedTeacherId}
+									<option value={teacher.id}>{teacher.firstName} {teacher.lastName}</option>
+								{/if}
+							{/each}
+						</select>
+					</div>
+				</div>
+
+				{#if selectedReplacedTeacherId && selectedReplacementTeacherId && selectedReplacedTeacherId === selectedReplacementTeacherId}
+					<div class="form-error">
+						L'enseignant remplacé et le remplaçant doivent être différents.
+					</div>
+				{/if}
+
+				<div class="form-row">
+					<div class="form-group">
+						<label for="start-date">Date de début *</label>
+						<input type="date" id="start-date" bind:value={selectedStartDate} required />
+					</div>
+
+					<div class="form-group">
+						<label for="end-date">Date de fin *</label>
+						<input type="date" id="end-date" bind:value={selectedEndDate} min={selectedStartDate} required />
+					</div>
+				</div>
+
+				{#if selectedStartDate && selectedEndDate && selectedEndDate < selectedStartDate}
+					<div class="form-error">
+						La date de fin doit être postérieure à la date de début.
+					</div>
+				{/if}
+
+				<div class="form-group" role="group" aria-labelledby="classes-label">
+					<span id="classes-label" class="form-label">Classes et matières concernées *</span>
+					{#each classPairs as pair, index}
+						<div class="class-pair-row">
+							<select bind:value={pair.classId} required>
+								<option value="">-- Classe --</option>
+								{#each classes as cls (cls.id)}
+									<option value={cls.id}>{cls.name}{cls.level ? ` (${cls.level})` : ''}</option>
+								{/each}
+							</select>
+							<select bind:value={pair.subjectId} required>
+								<option value="">-- Matière --</option>
+								{#each subjects as subject (subject.id)}
+									<option value={subject.id}>{subject.name} ({subject.code})</option>
+								{/each}
+							</select>
+							{#if classPairs.length > 1}
+								<button type="button" class="btn-remove-pair" onclick={() => removeClassPair(index)} aria-label="Retirer cette classe/matière">
+									x
+								</button>
+							{/if}
+						</div>
+					{/each}
+					<button type="button" class="btn-add-pair" onclick={addClassPair}>
+						+ Ajouter une classe/matière
+					</button>
+				</div>
+
+				<div class="form-group">
+					<label for="reason">Motif (optionnel)</label>
+					<input type="text" id="reason" bind:value={selectedReason} placeholder="Ex: Congé maladie" />
+				</div>
+
+				<div class="form-hint">
+					Le remplaçant pourra saisir de nouvelles notes et consulter les notes existantes en lecture seule.
+				</div>
+
+				<div class="modal-actions">
+					<button type="button" class="btn-secondary" onclick={closeCreateModal} disabled={isSubmitting}>
+						Annuler
+					</button>
+					<button
+						type="submit"
+						class="btn-primary"
+						disabled={isSubmitting || !isFormValid}
+					>
+						{#if isSubmitting}
+							Création...
+						{:else}
+							Désigner le remplaçant
+						{/if}
+					</button>
+				</div>
+			</form>
+		</div>
+	</div>
+{/if}
+
+<!-- End Replacement Confirmation Modal -->
+{#if showEndModal && replacementToEnd}
+	<!-- svelte-ignore a11y_no_static_element_interactions -->
+	<div class="modal-overlay" onclick={closeEndModal} role="presentation">
+		<div
+			class="modal modal-confirm"
+			role="alertdialog"
+			aria-modal="true"
+			aria-labelledby="end-modal-title"
+			aria-describedby="end-modal-description"
+			tabindex="-1"
+			onclick={(e) => e.stopPropagation()}
+			onkeydown={(e) => { if (e.key === 'Escape') closeEndModal(); }}
+		>
+			<header class="modal-header modal-header-danger">
+				<h2 id="end-modal-title">Terminer le remplacement</h2>
+				<button class="modal-close" onclick={closeEndModal} aria-label="Fermer">x</button>
+			</header>
+
+			<div class="modal-body">
+				<p id="end-modal-description">
+					Terminer le remplacement de <strong>{getTeacherName(replacementToEnd.replacedTeacherId)}</strong>
+					par <strong>{getTeacherName(replacementToEnd.replacementTeacherId)}</strong> ?
+				</p>
+				<p class="delete-warning">
+					Le remplaçant perdra immédiatement l'accès aux classes concernées.
+				</p>
+			</div>
+
+			<div class="modal-actions modal-actions-padded">
+				<button type="button" class="btn-secondary" onclick={closeEndModal} disabled={isEnding}>
+					Annuler
+				</button>
+				<button type="button" class="btn-danger" onclick={handleEnd} disabled={isEnding}>
+					{#if isEnding}
+						Terminaison...
+					{:else}
+						Terminer
+					{/if}
+				</button>
+			</div>
+		</div>
+	</div>
+{/if}
+
+<style>
+	.replacements-page {
+		padding: 1.5rem;
+		max-width: 1200px;
+		margin: 0 auto;
+	}
+
+	.page-header {
+		display: flex;
+		justify-content: space-between;
+		align-items: flex-start;
+		gap: 1rem;
+		margin-bottom: 1.5rem;
+		flex-wrap: wrap;
+	}
+
+	.header-content h1 {
+		margin: 0;
+		font-size: 1.5rem;
+		font-weight: 700;
+		color: #1f2937;
+	}
+
+	.subtitle {
+		margin: 0.25rem 0 0;
+		color: #6b7280;
+		font-size: 0.875rem;
+	}
+
+	/* Buttons */
+	.btn-primary {
+		display: inline-flex;
+		align-items: center;
+		gap: 0.5rem;
+		padding: 0.75rem 1.25rem;
+		background: #3b82f6;
+		color: white;
+		border: none;
+		border-radius: 0.5rem;
+		font-weight: 600;
+		cursor: pointer;
+		transition: background 0.2s;
+	}
+
+	.btn-primary:hover:not(:disabled) {
+		background: #2563eb;
+	}
+
+	.btn-primary:disabled {
+		opacity: 0.6;
+		cursor: not-allowed;
+	}
+
+	.btn-secondary {
+		padding: 0.5rem 1rem;
+		background: white;
+		color: #374151;
+		border: 1px solid #d1d5db;
+		border-radius: 0.375rem;
+		font-weight: 500;
+		cursor: pointer;
+		transition: all 0.2s;
+	}
+
+	.btn-secondary:hover:not(:disabled) {
+		background: #f3f4f6;
+	}
+
+	.btn-danger {
+		display: inline-flex;
+		align-items: center;
+		gap: 0.5rem;
+		padding: 0.5rem 1rem;
+		background: #dc2626;
+		color: white;
+		border: none;
+		border-radius: 0.375rem;
+		font-weight: 500;
+		cursor: pointer;
+		transition: background 0.2s;
+	}
+
+	.btn-danger:hover:not(:disabled) {
+		background: #b91c1c;
+	}
+
+	.btn-danger:disabled {
+		opacity: 0.6;
+		cursor: not-allowed;
+	}
+
+	.btn-remove {
+		padding: 0.375rem 0.75rem;
+		font-size: 0.75rem;
+		background: #fef2f2;
+		border: 1px solid #fecaca;
+		color: #991b1b;
+		border-radius: 0.25rem;
+		cursor: pointer;
+		transition: background 0.15s;
+	}
+
+	.btn-remove:hover {
+		background: #fee2e2;
+	}
+
+	.btn-icon {
+		font-size: 1.25rem;
+		line-height: 1;
+	}
+
+	/* Alerts */
+	.alert {
+		display: flex;
+		align-items: center;
+		gap: 0.75rem;
+		padding: 1rem;
+		border-radius: 0.5rem;
+		margin-bottom: 1rem;
+	}
+
+	.alert-error {
+		background: #fef2f2;
+		border: 1px solid #fecaca;
+		color: #dc2626;
+	}
+
+	.alert-success {
+		background: #f0fdf4;
+		border: 1px solid #bbf7d0;
+		color: #16a34a;
+	}
+
+	.alert-icon {
+		flex-shrink: 0;
+		font-weight: bold;
+	}
+
+	.alert-close {
+		margin-left: auto;
+		padding: 0.25rem 0.5rem;
+		background: none;
+		border: none;
+		font-size: 1.25rem;
+		cursor: pointer;
+		opacity: 0.6;
+	}
+
+	.alert-close:hover {
+		opacity: 1;
+	}
+
+	/* Loading & Empty */
+	.loading-state,
+	.empty-state {
+		display: flex;
+		flex-direction: column;
+		align-items: center;
+		justify-content: center;
+		padding: 3rem;
+		text-align: center;
+		background: white;
+		border-radius: 0.75rem;
+		border: 2px dashed #e5e7eb;
+	}
+
+	.spinner {
+		width: 2rem;
+		height: 2rem;
+		border: 3px solid #e5e7eb;
+		border-top-color: #3b82f6;
+		border-radius: 50%;
+		animation: spin 0.8s linear infinite;
+	}
+
+	@keyframes spin {
+		to {
+			transform: rotate(360deg);
+		}
+	}
+
+	.empty-icon {
+		font-size: 3rem;
+		margin-bottom: 1rem;
+	}
+
+	.empty-state h2 {
+		margin: 0 0 0.5rem;
+		font-size: 1.25rem;
+		color: #1f2937;
+	}
+
+	.empty-state p {
+		margin: 0 0 1.5rem;
+		color: #6b7280;
+	}
+
+	/* Table */
+	.table-container {
+		background: white;
+		border: 1px solid #e5e7eb;
+		border-radius: 0.75rem;
+		overflow-x: auto;
+	}
+
+	.replacements-table {
+		width: 100%;
+		border-collapse: collapse;
+	}
+
+	.replacements-table th {
+		text-align: left;
+		padding: 0.75rem 1rem;
+		font-size: 0.75rem;
+		font-weight: 600;
+		color: #6b7280;
+		text-transform: uppercase;
+		letter-spacing: 0.05em;
+		border-bottom: 1px solid #e5e7eb;
+		background: #f9fafb;
+	}
+
+	.replacements-table td {
+		padding: 0.75rem 1rem;
+		font-size: 0.875rem;
+		color: #374151;
+		border-bottom: 1px solid #f3f4f6;
+		vertical-align: top;
+	}
+
+	.replacements-table tr:last-child td {
+		border-bottom: none;
+	}
+
+	.replacements-table tr:hover td {
+		background: #f9fafb;
+	}
+
+	.teacher-cell {
+		white-space: nowrap;
+	}
+
+	.teacher-name {
+		font-weight: 500;
+		color: #1f2937;
+	}
+
+	.classes-cell {
+		min-width: 200px;
+	}
+
+	.class-pair {
+		display: inline-flex;
+		align-items: center;
+		gap: 0.25rem;
+		margin: 0.125rem 0.25rem 0.125rem 0;
+	}
+
+	.class-name {
+		font-size: 0.8125rem;
+		color: #4b5563;
+	}
+
+	.subject-badge {
+		display: inline-block;
+		padding: 0.125rem 0.5rem;
+		border-radius: 9999px;
+		font-size: 0.6875rem;
+		font-weight: 500;
+	}
+
+	.subject-badge-default {
+		background: #f3f4f6;
+		color: #374151;
+	}
+
+	.date-cell {
+		white-space: nowrap;
+	}
+
+	.date-range {
+		color: #374151;
+		font-size: 0.8125rem;
+	}
+
+	.countdown {
+		display: block;
+		margin-top: 0.25rem;
+		font-size: 0.75rem;
+		font-weight: 500;
+		color: #16a34a;
+	}
+
+	.countdown-warning {
+		color: #d97706;
+	}
+
+	.countdown-urgent {
+		color: #dc2626;
+	}
+
+	.status-badge {
+		display: inline-block;
+		padding: 0.125rem 0.5rem;
+		border-radius: 9999px;
+		font-size: 0.75rem;
+		font-weight: 500;
+	}
+
+	.status-active {
+		background: #f0fdf4;
+		color: #16a34a;
+	}
+
+	.status-ended {
+		background: #f3f4f6;
+		color: #6b7280;
+	}
+
+	.actions-cell {
+		white-space: nowrap;
+	}
+
+	/* Modal */
+	.modal-overlay {
+		position: fixed;
+		inset: 0;
+		background: rgba(0, 0, 0, 0.5);
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		padding: 1rem;
+		z-index: 100;
+	}
+
+	.modal {
+		background: white;
+		border-radius: 0.75rem;
+		width: 100%;
+		max-width: 28rem;
+		max-height: 90vh;
+		overflow: auto;
+		box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
+	}
+
+	.modal-large {
+		max-width: 36rem;
+	}
+
+	.modal-header {
+		display: flex;
+		align-items: center;
+		justify-content: space-between;
+		padding: 1.25rem 1.5rem;
+		border-bottom: 1px solid #e5e7eb;
+	}
+
+	.modal-header h2 {
+		margin: 0;
+		font-size: 1.125rem;
+		font-weight: 600;
+		color: #1f2937;
+	}
+
+	.modal-close {
+		padding: 0.25rem 0.5rem;
+		background: none;
+		border: none;
+		font-size: 1.5rem;
+		line-height: 1;
+		color: #6b7280;
+		cursor: pointer;
+	}
+
+	.modal-close:hover {
+		color: #1f2937;
+	}
+
+	.modal-body {
+		padding: 1.5rem;
+	}
+
+	.form-row {
+		display: grid;
+		grid-template-columns: 1fr 1fr;
+		gap: 1rem;
+	}
+
+	.form-group {
+		margin-bottom: 1.25rem;
+	}
+
+	.form-group label,
+	.form-label {
+		display: block;
+		margin-bottom: 0.5rem;
+		font-weight: 500;
+		color: #374151;
+	}
+
+	.form-group select,
+	.form-group input {
+		width: 100%;
+		padding: 0.75rem 1rem;
+		border: 1px solid #d1d5db;
+		border-radius: 0.375rem;
+		font-size: 1rem;
+		transition: border-color 0.2s;
+		background: white;
+	}
+
+	.form-group select:focus,
+	.form-group input:focus {
+		outline: none;
+		border-color: #3b82f6;
+		box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
+	}
+
+	.form-error {
+		padding: 0.5rem 0.75rem;
+		background: #fef2f2;
+		border: 1px solid #fecaca;
+		border-radius: 0.375rem;
+		color: #dc2626;
+		font-size: 0.875rem;
+		margin-bottom: 1rem;
+	}
+
+	.class-pair-row {
+		display: grid;
+		grid-template-columns: 1fr 1fr auto;
+		gap: 0.5rem;
+		margin-bottom: 0.5rem;
+		align-items: center;
+	}
+
+	.class-pair-row select {
+		padding: 0.5rem 0.75rem;
+		border: 1px solid #d1d5db;
+		border-radius: 0.375rem;
+		font-size: 0.875rem;
+		background: white;
+	}
+
+	.class-pair-row select:focus {
+		outline: none;
+		border-color: #3b82f6;
+		box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
+	}
+
+	.btn-remove-pair {
+		padding: 0.375rem 0.5rem;
+		background: #fef2f2;
+		border: 1px solid #fecaca;
+		color: #991b1b;
+		border-radius: 0.25rem;
+		cursor: pointer;
+		font-size: 0.875rem;
+		line-height: 1;
+	}
+
+	.btn-remove-pair:hover {
+		background: #fee2e2;
+	}
+
+	.btn-add-pair {
+		padding: 0.5rem 0.75rem;
+		background: none;
+		border: 1px dashed #d1d5db;
+		border-radius: 0.375rem;
+		color: #6b7280;
+		cursor: pointer;
+		font-size: 0.875rem;
+		width: 100%;
+		transition: all 0.2s;
+	}
+
+	.btn-add-pair:hover {
+		border-color: #3b82f6;
+		color: #3b82f6;
+		background: #eff6ff;
+	}
+
+	.form-hint {
+		padding: 0.75rem 1rem;
+		background: #eff6ff;
+		border-radius: 0.375rem;
+		font-size: 0.875rem;
+		color: #3b82f6;
+		margin-bottom: 1.25rem;
+	}
+
+	.modal-actions {
+		display: flex;
+		justify-content: flex-end;
+		gap: 0.75rem;
+		padding-top: 1rem;
+		border-top: 1px solid #e5e7eb;
+	}
+
+	.modal-actions-padded {
+		padding: 1rem 1.5rem;
+	}
+
+	/* End confirmation modal */
+	.modal-confirm {
+		max-width: 24rem;
+	}
+
+	.modal-header-danger {
+		background: #fef2f2;
+		border-bottom-color: #fecaca;
+	}
+
+	.modal-header-danger h2 {
+		color: #dc2626;
+	}
+
+	.delete-warning {
+		margin: 0.75rem 0 0;
+		font-size: 0.875rem;
+		color: #6b7280;
+	}
+
+	@media (max-width: 640px) {
+		.form-row {
+			grid-template-columns: 1fr;
+		}
+
+		.class-pair-row {
+			grid-template-columns: 1fr;
+		}
+	}
+
+	@media (max-width: 767px) {
+		.table-container {
+			background: transparent;
+			border: none;
+		}
+
+		.replacements-table thead {
+			display: none;
+		}
+
+		.replacements-table tbody tr {
+			display: block;
+			background: white;
+			border: 1px solid #e5e7eb;
+			border-radius: 0.75rem;
+			margin-bottom: 0.75rem;
+			padding: 0.25rem 0;
+		}
+
+		.replacements-table tr:hover td {
+			background: transparent;
+		}
+
+		.replacements-table td {
+			display: flex;
+			justify-content: space-between;
+			align-items: baseline;
+			padding: 0.5rem 1rem;
+			border-bottom: none;
+			text-align: right;
+		}
+
+		.replacements-table td::before {
+			content: attr(data-label);
+			font-weight: 600;
+			font-size: 0.75rem;
+			color: #6b7280;
+			text-transform: uppercase;
+			letter-spacing: 0.05em;
+			text-align: left;
+			margin-right: 1rem;
+			flex-shrink: 0;
+		}
+
+		.teacher-cell {
+			white-space: normal;
+		}
+
+		.classes-cell {
+			min-width: 0;
+		}
+
+		.date-cell {
+			white-space: normal;
+		}
+
+		.actions-cell {
+			justify-content: flex-end;
+			padding-top: 0.75rem;
+			border-top: 1px solid #f3f4f6;
+		}
+	}
+</style>
diff --git a/frontend/src/routes/admin/users/+page.svelte b/frontend/src/routes/admin/users/+page.svelte
index 2074bda..0a62cca 100644
--- a/frontend/src/routes/admin/users/+page.svelte
+++ b/frontend/src/routes/admin/users/+page.svelte
@@ -569,11 +569,11 @@
 				<tbody>
 					{#each users as user (user.id)}
 						<tr>
-							<td class="user-name-cell">
+							<td data-label="Nom" class="user-name-cell">
 								<span class="user-fullname">{user.firstName} {user.lastName}</span>
 							</td>
-							<td class="user-email">{user.email}</td>
-							<td>
+							<td data-label="Email" class="user-email">{user.email}</td>
+							<td data-label="Rôle">
 								<div class="role-badges">
 									{#if user.roles && user.roles.length > 0}
 										{#each user.roles as roleValue}
@@ -584,7 +584,7 @@
 									{/if}
 								</div>
 							</td>
-							<td>
+							<td data-label="Statut">
 								<span class="status-badge {getStatutClass(user.statut, user.invitationExpiree)}">
 									{getStatutDisplay(user.statut, user.invitationExpiree)}
 								</span>
@@ -594,8 +594,8 @@
 									</span>
 								{/if}
 							</td>
-							<td class="date-cell">{formatDate(user.invitedAt)}</td>
-							<td class="actions-cell">
+							<td data-label="Invitation" class="date-cell">{formatDate(user.invitedAt)}</td>
+							<td data-label="Actions" class="actions-cell">
 								{#if user.id !== getCurrentUserId()}
 									<button
 										class="btn-secondary btn-sm"
@@ -1196,11 +1196,6 @@
 		background: #f9fafb;
 	}
 
-	.users-table th:nth-child(5),
-	.users-table td:nth-child(5) {
-		display: none;
-	}
-
 	.user-name-cell {
 		white-space: nowrap;
 	}
@@ -1481,10 +1476,61 @@
 		.form-row {
 			grid-template-columns: 1fr 1fr;
 		}
+	}
 
-		.users-table th:nth-child(5),
-		.users-table td:nth-child(5) {
-			display: table-cell;
+	@media (max-width: 767px) {
+		.users-table-container {
+			background: transparent;
+			border: none;
+		}
+
+		.users-table thead {
+			display: none;
+		}
+
+		.users-table tbody tr {
+			display: block;
+			background: white;
+			border: 1px solid #e5e7eb;
+			border-radius: 0.75rem;
+			margin-bottom: 0.75rem;
+			padding: 0.25rem 0;
+		}
+
+		.users-table tr:hover td {
+			background: transparent;
+		}
+
+		.users-table td {
+			display: flex;
+			justify-content: space-between;
+			align-items: baseline;
+			padding: 0.5rem 1rem;
+			border-bottom: none;
+			text-align: right;
+		}
+
+		.users-table td::before {
+			content: attr(data-label);
+			font-weight: 600;
+			font-size: 0.75rem;
+			color: #6b7280;
+			text-transform: uppercase;
+			letter-spacing: 0.05em;
+			text-align: left;
+			margin-right: 1rem;
+			flex-shrink: 0;
+		}
+
+		.user-name-cell {
+			white-space: normal;
+		}
+
+		.actions-cell {
+			justify-content: flex-end;
+			flex-wrap: wrap;
+			padding-top: 0.75rem;
+			border-top: 1px solid #f3f4f6;
 		}
 	}
 </style>