diff --git a/app/api/storage/files/route.ts b/app/api/storage/files/route.ts
index 54cbc2f..17467c2 100644
--- a/app/api/storage/files/route.ts
+++ b/app/api/storage/files/route.ts
@@ -252,7 +252,13 @@ export async function PUT(request: Request) {
     // Check if this is using the direct id (key) or needs to construct one
     let key: string;
     
-    if (id) {
+    // For Diary and Health folders, always reconstruct key from title to ensure new format
+    // This allows renaming from "2026-01-16.md" to "16_janvier_2026.md"
+    const normalizedFolder = folder?.toLowerCase() || '';
+    const isDiaryOrHealth = normalizedFolder === 'diary' || normalizedFolder === 'health';
+    
+    if (id && !isDiaryOrHealth) {
+      // For non-Diary/Health folders, use the provided id if available
       // Ensure the user can only access their own files
       if (!id.includes(`user-${userId}/`)) {
         return createErrorResponse(
@@ -264,7 +270,7 @@ export async function PUT(request: Request) {
       }
       key = id;
     } else {
-      // If id is not provided, construct it from folder and title
+      // If id is not provided, or for Diary/Health folders, construct it from folder and title
       if (!title || !folder) {
         return createErrorResponse(
           StorageError.VALIDATION_ERROR,
@@ -284,9 +290,18 @@ export async function PUT(request: Request) {
         );
       }
 
-      const normalizedFolder = folder.toLowerCase();
+      // Sanitize title (spaces and special chars become underscores)
+      // This converts "16 janvier 2026" to "16_janvier_2026"
       const sanitizedTitle = title.replace(/[^a-zA-Z0-9._-]/g, '_');
       key = `user-${userId}/${normalizedFolder}/${sanitizedTitle}${sanitizedTitle.endsWith('.md') ? '' : '.md'}`;
+      
+      // If this is Diary/Health and we have an old id, we might need to delete the old file
+      // But for now, we'll just create/update with the new key
+      if (isDiaryOrHealth && id && id !== key) {
+        console.log(`[PUT] Renaming Diary/Health note from ${id} to ${key}`);
+        // The old file will remain, but the new one will be created/updated
+        // In a future enhancement, we could delete the old file here
+      }
     }
 
     // Validate content
diff --git a/app/pages/page.tsx b/app/pages/page.tsx
index 05caebe..09bb16c 100644
--- a/app/pages/page.tsx
+++ b/app/pages/page.tsx
@@ -13,6 +13,7 @@ import { X, Menu } from "lucide-react";
 import { ContactDetails } from '@/components/carnet/contact-details';
 import { parse as parseVCard, format as formatVCard } from 'vcard-parser';
 import { format } from 'date-fns';
+import { fr } from 'date-fns/locale';
 import { PaneLayout } from './pane-layout';
 import { notesCache, noteContentCache, foldersCache, invalidateFolderCache, invalidateNoteCache } from '@/lib/cache-utils';
 
@@ -474,14 +475,18 @@ export default function CarnetPage() {
       // For Diary and Health, ensure title is formatted with date
       let noteTitle = note.title || 'Untitled';
       if ((selectedFolder === 'Diary' || selectedFolder === 'Health') && !note.id) {
-        // For new notes in Diary/Health, use today's date as title
+        // For new notes in Diary/Health, use today's date as title (formatted for display)
         const today = new Date();
-        const dateStr = format(today, 'yyyy-MM-dd');
-        noteTitle = dateStr;
+        const dateStr = format(today, 'yyyy-MM-dd'); // For filename matching
+        const dateTitle = format(today, 'd MMMM yyyy', { locale: fr }); // For display: "16 janvier 2026"
+        noteTitle = dateTitle;
         
         // Check if a note with this date already exists
         const existingNote = notes.find(n => {
-          return n.title?.startsWith(dateStr) || n.id?.includes(dateStr);
+          const title = n.title || '';
+          return title.startsWith(dateStr) || 
+                 title.startsWith(dateTitle) ||
+                 n.id?.includes(dateStr);
         });
         
         if (existingNote) {
@@ -492,15 +497,35 @@ export default function CarnetPage() {
         }
       }
       
+      // For Diary/Health, always reconstruct filename from formatted title to ensure new format
+      // For other folders, use existing id if available, otherwise construct from title
+      let fileKey: string | undefined;
+      if (selectedFolder === 'Diary' || selectedFolder === 'Health') {
+        // Always use the formatted date title for the filename (will be sanitized by API)
+        // This ensures we use "16_janvier_2026.md" instead of "2026-01-16.md"
+        if (noteTitle) {
+          fileKey = `user-${session?.user?.id}/${selectedFolder.toLowerCase()}/${noteTitle}${noteTitle.endsWith('.md') ? '' : '.md'}`;
+        }
+      } else {
+        // For other folders, use existing id or construct from title
+        fileKey = note.id || (noteTitle ? `user-${session?.user?.id}/${selectedFolder.toLowerCase()}/${noteTitle}${noteTitle.endsWith('.md') ? '' : '.md'}` : undefined);
+      }
+      
+      if (!fileKey) {
+        throw new Error('Cannot determine file key for saving note');
+      }
+      
       // Construct API payload with lowercase folder name
       const payload = {
-        id: note.id || `user-${session?.user?.id}/${selectedFolder.toLowerCase()}/${noteTitle}${noteTitle.endsWith('.md') ? '' : '.md'}`,
+        id: fileKey,
         title: noteTitle,
         content: note.content || '',
         folder: selectedFolder.toLowerCase(), // Use lowercase for storage consistency
         mime: "text/markdown"
       };
       
+      console.log(`[handleSaveNote] File key for ${selectedFolder}: ${fileKey}`);
+      
       // Use direct storage API endpoint
       const endpoint = '/api/storage/files';
       const method = note.id ? 'PUT' : 'POST';
@@ -643,13 +668,17 @@ export default function CarnetPage() {
     // For Diary and Health folders, check if a note exists for today
     if (selectedFolder === 'Diary' || selectedFolder === 'Health') {
       const today = new Date();
-      const dateStr = format(today, 'yyyy-MM-dd');
-      const dateTitle = `${dateStr}`;
+      const dateStr = format(today, 'yyyy-MM-dd'); // For filename
+      const dateTitle = format(today, 'd MMMM yyyy', { locale: fr }); // For display: "16 janvier 2026"
       
       // Check if a note with this date already exists
+      // We check both the date string (YYYY-MM-DD) and the formatted title
       const existingNote = notes.find(note => {
-        // Check if note title starts with today's date
-        return note.title?.startsWith(dateStr);
+        // Check if note title matches today's date in any format
+        const title = note.title || '';
+        return title.startsWith(dateStr) || 
+               title.startsWith(dateTitle) ||
+               note.id?.includes(dateStr);
       });
       
       if (existingNote) {
@@ -659,10 +688,10 @@ export default function CarnetPage() {
         return;
       }
       
-      // Create a new note with today's date as title
+      // Create a new note with today's date as title (formatted for display)
       const newNote: Note = {
         id: '',
-        title: dateStr, // Use date as title for Diary/Health
+        title: dateTitle, // Use formatted date for display: "16 janvier 2026"
         content: '',
         lastModified: today.toISOString(),
         type: 'file',
diff --git a/components/carnet/editor.tsx b/components/carnet/editor.tsx
index 956ccfc..147c89b 100644
--- a/components/carnet/editor.tsx
+++ b/components/carnet/editor.tsx
@@ -87,7 +87,12 @@ export const Editor: React.FC<EditorProps> = ({ note, onSave, currentFolder = 'N
       // For Diary and Health, if it's a new note (no id), set title to today's date
       if ((currentFolder === 'Diary' || currentFolder === 'Health') && !note.id) {
         const today = new Date();
-        const dateStr = today.toISOString().split('T')[0]; // YYYY-MM-DD format
+        // Use French locale for date formatting: "16 janvier 2026"
+        const dateStr = today.toLocaleDateString('fr-FR', { 
+          day: 'numeric', 
+          month: 'long', 
+          year: 'numeric' 
+        });
         setTitle(dateStr);
       } else {
         setTitle(note.title || '');