diff --git a/app/api/missions/[missionId]/files/folder/route.ts b/app/api/missions/[missionId]/files/folder/route.ts
index 35eceee..867fa66 100644
--- a/app/api/missions/[missionId]/files/folder/route.ts
+++ b/app/api/missions/[missionId]/files/folder/route.ts
@@ -19,11 +19,13 @@ const missionsS3Client = new S3Client({
 const MISSIONS_BUCKET = 'missions';
 
 // Helper function to check if user can manage files (creator or gardien)
-async function checkCanManage(userId: string, missionId: string): Promise<boolean> {
+// Also checks if mission is closed (closed missions cannot be modified)
+async function checkCanManage(userId: string, missionId: string): Promise<{ canManage: boolean; isClosed: boolean }> {
   const mission = await prisma.mission.findFirst({
     where: { id: missionId },
     select: {
       creatorId: true,
+      isClosed: true,
       missionUsers: {
         where: { userId },
         select: { role: true }
@@ -31,14 +33,20 @@ async function checkCanManage(userId: string, missionId: string): Promise<boolea
     }
   });
 
-  if (!mission) return false;
+  if (!mission) return { canManage: false, isClosed: false };
+  
+  // If mission is closed, no one can manage files
+  if (mission.isClosed) {
+    return { canManage: false, isClosed: true };
+  }
   
   // Creator can always manage
-  if (mission.creatorId === userId) return true;
+  if (mission.creatorId === userId) return { canManage: true, isClosed: false };
   
   // Gardiens can manage
   const userRole = mission.missionUsers[0]?.role;
-  return userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
+  const canManage = userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
+  return { canManage, isClosed: false };
 }
 
 export async function POST(
@@ -54,8 +62,11 @@ export async function POST(
     const { missionId } = await params;
     const userId = session.user.id;
 
-    // Check if user can manage files
-    const canManage = await checkCanManage(userId, missionId);
+    // Check if user can manage files and if mission is closed
+    const { canManage, isClosed } = await checkCanManage(userId, missionId);
+    if (isClosed) {
+      return NextResponse.json({ error: 'Mission is closed: folders cannot be created in closed missions' }, { status: 403 });
+    }
     if (!canManage) {
       return NextResponse.json({ error: 'Forbidden: You do not have permission to create folders' }, { status: 403 });
     }
diff --git a/app/api/missions/[missionId]/files/route.ts b/app/api/missions/[missionId]/files/route.ts
index 3cc395f..60ce9ff 100644
--- a/app/api/missions/[missionId]/files/route.ts
+++ b/app/api/missions/[missionId]/files/route.ts
@@ -34,11 +34,13 @@ async function checkMissionAccess(userId: string, missionId: string): Promise<bo
 }
 
 // Helper function to check if user can manage files (creator or gardien)
-async function checkCanManage(userId: string, missionId: string): Promise<boolean> {
+// Also checks if mission is closed (closed missions cannot be modified)
+async function checkCanManage(userId: string, missionId: string): Promise<{ canManage: boolean; isClosed: boolean }> {
   const mission = await prisma.mission.findFirst({
     where: { id: missionId },
     select: {
       creatorId: true,
+      isClosed: true,
       missionUsers: {
         where: { userId },
         select: { role: true }
@@ -46,14 +48,20 @@ async function checkCanManage(userId: string, missionId: string): Promise<boolea
     }
   });
 
-  if (!mission) return false;
+  if (!mission) return { canManage: false, isClosed: false };
+  
+  // If mission is closed, no one can manage files
+  if (mission.isClosed) {
+    return { canManage: false, isClosed: true };
+  }
   
   // Creator can always manage
-  if (mission.creatorId === userId) return true;
+  if (mission.creatorId === userId) return { canManage: true, isClosed: false };
   
   // Gardiens can manage
   const userRole = mission.missionUsers[0]?.role;
-  return userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
+  const canManage = userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
+  return { canManage, isClosed: false };
 }
 
 // Helper function to stream to string
@@ -323,8 +331,11 @@ export async function DELETE(
     const { missionId } = await params;
     const userId = session.user.id;
 
-    // Check if user can manage files
-    const canManage = await checkCanManage(userId, missionId);
+    // Check if user can manage files and if mission is closed
+    const { canManage, isClosed } = await checkCanManage(userId, missionId);
+    if (isClosed) {
+      return NextResponse.json({ error: 'Mission is closed: files cannot be deleted from closed missions' }, { status: 403 });
+    }
     if (!canManage) {
       return NextResponse.json({ error: 'Forbidden: You do not have permission to delete files' }, { status: 403 });
     }
diff --git a/app/api/missions/[missionId]/files/upload/route.ts b/app/api/missions/[missionId]/files/upload/route.ts
index 0099571..f06a957 100644
--- a/app/api/missions/[missionId]/files/upload/route.ts
+++ b/app/api/missions/[missionId]/files/upload/route.ts
@@ -5,11 +5,13 @@ import { prisma } from '@/lib/prisma';
 import { uploadMissionAttachment } from '@/lib/mission-uploads';
 
 // Helper function to check if user can manage files (creator or gardien)
-async function checkCanManage(userId: string, missionId: string): Promise<boolean> {
+// Also checks if mission is closed (closed missions cannot be modified)
+async function checkCanManage(userId: string, missionId: string): Promise<{ canManage: boolean; isClosed: boolean }> {
   const mission = await prisma.mission.findFirst({
     where: { id: missionId },
     select: {
       creatorId: true,
+      isClosed: true,
       missionUsers: {
         where: { userId },
         select: { role: true }
@@ -17,14 +19,20 @@ async function checkCanManage(userId: string, missionId: string): Promise<boolea
     }
   });
 
-  if (!mission) return false;
+  if (!mission) return { canManage: false, isClosed: false };
+  
+  // If mission is closed, no one can manage files
+  if (mission.isClosed) {
+    return { canManage: false, isClosed: true };
+  }
   
   // Creator can always manage
-  if (mission.creatorId === userId) return true;
+  if (mission.creatorId === userId) return { canManage: true, isClosed: false };
   
   // Gardiens can manage
   const userRole = mission.missionUsers[0]?.role;
-  return userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
+  const canManage = userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
+  return { canManage, isClosed: false };
 }
 
 export async function POST(
@@ -40,8 +48,11 @@ export async function POST(
     const { missionId } = await params;
     const userId = session.user.id;
 
-    // Check if user can manage files
-    const canManage = await checkCanManage(userId, missionId);
+    // Check if user can manage files and if mission is closed
+    const { canManage, isClosed } = await checkCanManage(userId, missionId);
+    if (isClosed) {
+      return NextResponse.json({ error: 'Mission is closed: files cannot be uploaded to closed missions' }, { status: 403 });
+    }
     if (!canManage) {
       return NextResponse.json({ error: 'Forbidden: You do not have permission to upload files' }, { status: 403 });
     }
diff --git a/app/api/missions/[missionId]/route.ts b/app/api/missions/[missionId]/route.ts
index 800f317..9e2620c 100644
--- a/app/api/missions/[missionId]/route.ts
+++ b/app/api/missions/[missionId]/route.ts
@@ -30,6 +30,7 @@ export async function GET(
         id: true,
         name: true,
         creatorId: true,
+        isClosed: true,
         creator: {
           select: {
             id: true,
diff --git a/app/pages/page.tsx b/app/pages/page.tsx
index 3b60456..e12b38f 100644
--- a/app/pages/page.tsx
+++ b/app/pages/page.tsx
@@ -708,6 +708,7 @@ export default function CarnetPage() {
           id: missionData.id,
           name: missionData.name,
           creatorId: missionData.creatorId || missionData.creator?.id,
+          isClosed: missionData.isClosed || false,
           missionUsers: missionData.missionUsers || []
         });
       } else {
@@ -1182,6 +1183,7 @@ export default function CarnetPage() {
                       id: selectedMission.id,
                       name: selectedMission.name,
                       creatorId: selectedMission.creatorId || '',
+                      isClosed: selectedMission.isClosed || false,
                       missionUsers: selectedMission.missionUsers || []
                     }}
                     currentUserId={session.user.id}
diff --git a/components/carnet/mission-files-manager.tsx b/components/carnet/mission-files-manager.tsx
index 8f2fb03..dc46765 100644
--- a/components/carnet/mission-files-manager.tsx
+++ b/components/carnet/mission-files-manager.tsx
@@ -21,6 +21,7 @@ interface Mission {
   id: string;
   name: string;
   creatorId: string;
+  isClosed?: boolean;
   missionUsers?: MissionUser[];
 }
 
@@ -50,7 +51,8 @@ export const MissionFilesManager: React.FC<MissionFilesManagerProps> = ({
   const isCreator = mission.creatorId === currentUserId;
   const userRole = mission.missionUsers?.find(mu => mu.userId === currentUserId)?.role;
   const isGardien = userRole === 'gardien-temps' || userRole === 'gardien-parole' || userRole === 'gardien-memoire';
-  const canManage = isCreator || isGardien;
+  const isClosed = mission.isClosed || false;
+  const canManage = (isCreator || isGardien) && !isClosed; // Cannot manage if mission is closed
 
   const fetchFiles = async () => {
     try {