diff --git a/app/scodoc/sco_groups.py b/app/scodoc/sco_groups.py
index 79ed91cad..6df63bef3 100644
--- a/app/scodoc/sco_groups.py
+++ b/app/scodoc/sco_groups.py
@@ -599,6 +599,11 @@ def XMLgetGroupsInPartition(partition_id):  # was XMLgetGroupesTD
     response.headers["Content-Type"] = scu.XML_MIMETYPE
     return response
 
+def check_group_name(group_name, partition):
+    """Raise ScoValueError if group_name exists in partition"""
+    exists = group_name in [g["group_name"] for g in get_partition_groups(partition)]
+    if exists:
+        raise ScoValueError("Le nom de groupe existe déjà dans la partition")
 
 def comp_origin(etud, cur_sem):
     """breve description de l'origine de l'étudiant (sem. precedent)
@@ -1244,6 +1249,7 @@ def group_set_name(group_id, group_name, redirect=True):
     if not sco_permissions_check.can_change_groups(formsemestre_id):
         raise AccessDenied("Vous n'avez pas le droit d'effectuer cette opération !")
     redirect = int(redirect)
+    check_group_name(group_name, get_partition(group['partition_id']))
     cnx = ndb.GetDBConnexion()
     groupEditor.edit(cnx, {"group_id": group_id, "group_name": group_name})
 
@@ -1372,13 +1378,13 @@ def groups_auto_repartition(partition_id=None):
         # Crée les nouveaux groupes
         group_ids = []
         for group_name in group_names:
-            # try:
-            #     checkGroupName(group_name)
-            # except:
-            #     H.append('<p class="warning">Nom de groupe invalide: %s</p>'%group_name)
-            #     return '\n'.join(H) + tf[1] + html_sco_header.sco_footer()
+            try:
+                check_group_name(group_name, partition)
+            except:
+                H.append('<p class="warning">Nom de groupe invalide: %s</p>'%group_name)
+                return '\n'.join(H) + tf[1] + html_sco_header.sco_footer()
             group_ids.append(create_group(partition_id, group_name))
-        #
+        
         nt: NotesTableCompat = res_sem.load_formsemestre_results(formsemestre)
         identdict = nt.identdict
         # build:  { civilite : liste etudids trie par niveau croissant }