diff --git a/giving_names.py b/giving_names.py
index 550e5d1..a10e05e 100644
--- a/giving_names.py
+++ b/giving_names.py
@@ -3,6 +3,7 @@ import sys
 import json
 import shutil
 import re
+from collections import defaultdict
 
 def main():
     if len(sys.argv) < 2:
@@ -12,12 +13,14 @@ def main():
     work_dir = sys.argv[1]
     target_subdir = os.path.join(work_dir, "Copies annotées")
 
-    # Create destination folder if it doesn't exist
     os.makedirs(target_subdir, exist_ok=True)
 
-    # Regex to match "CopieXX.json" and capture XX
     pattern = re.compile(r"^Copie(\d+)\.json$")
 
+    # Store data: name -> list of (copie_id, source_folder)
+    copies_map = defaultdict(list)
+
+    # 1. Collect all data
     for filename in os.listdir(work_dir):
         match = pattern.match(filename)
         if match:
@@ -25,24 +28,38 @@ def main():
             json_path = os.path.join(work_dir, filename)
             source_folder = os.path.join(work_dir, f"Anot_Copie{copie_id}")
 
-            # Check if corresponding folder exists
             if os.path.isdir(source_folder):
                 try:
                     with open(json_path, 'r', encoding='utf-8') as f:
                         data = json.load(f)
                         name = data.get("name", "Unknown").strip()
-
-                        # Sanitize filename (remove characters invalid in paths)
-                        safe_name = re.sub(r'[<>:"/\\|?*]', '', name)
-
-                        new_folder_name = f"{safe_name} ({copie_id})"
-                        dest_path = os.path.join(target_subdir, new_folder_name)
-
-                        print(f"Moving '{source_folder}' -> '{dest_path}'")
-                        shutil.move(source_folder, dest_path)
-
+                        copies_map[name].append((copie_id, source_folder))
                 except Exception as e:
                     print(f"Error processing {filename}: {e}")
 
+    # 2. Check constraints and move files
+    for name, entries in copies_map.items():
+        # Alert if name is Unknown
+        if name == "Unknown":
+            ids = [e[0] for e in entries]
+            print(f"ALERT: 'Unknown' name found for IDs: {', '.join(ids)}")
+
+        # Alert if duplicates (same name, multiple IDs)
+        elif len(entries) > 1:
+            ids = [e[0] for e in entries]
+            print(f"ALERT: Name '{name}' assigned to multiple IDs: {', '.join(ids)}")
+
+        # Perform move
+        safe_name = re.sub(r'[<>:"/\\|?*]', '', name)
+        for copie_id, source_folder in entries:
+            new_folder_name = f"{safe_name} ({copie_id})"
+            dest_path = os.path.join(target_subdir, new_folder_name)
+
+            try:
+                print(f"Moving '{source_folder}' -> '{dest_path}'")
+                shutil.move(source_folder, dest_path)
+            except Exception as e:
+                print(f"Error moving {source_folder}: {e}")
+
 if __name__ == "__main__":
     main()