diff --git a/app/scodoc/sco_groups.py b/app/scodoc/sco_groups.py
index 79ed91ca..4f984d0b 100644
--- a/app/scodoc/sco_groups.py
+++ b/app/scodoc/sco_groups.py
@@ -263,6 +263,15 @@ def get_group_members(group_id, etat=None):
 
     return r
 
+def check_group_name(group_name, partition, raiser=False):
+    """If groupe name exists in partition : if raiser -> Raise ScoValueError else-> return true"""
+    exists = group_name in [g["group_name"] for g in get_partition_groups(partition)]
+    if exists:
+        if raiser:
+            raise ScoValueError("Le nom de groupe existe déjà dans la partition")
+        else :
+            return True
+    return False;
 
 # obsolete:  sco_groups_view.DisplayedGroupsInfos
 # def get_groups_members(group_ids, etat=None):
@@ -798,7 +807,7 @@ def create_group(partition_id, group_name="", default=False) -> int:
     if not group_name and not default:
         raise ValueError("invalid group name: ()")
     # checkGroupName(group_name)
-    if group_name in [g["group_name"] for g in get_partition_groups(partition)]:
+    if check_group_name(group_name, partition):
         raise ValueError(
             "group_name %s already exists in partition" % group_name
         )  # XXX FIX: incorrect error handling (in AJAX)
@@ -1246,7 +1255,7 @@ def group_set_name(group_id, group_name, redirect=True):
     redirect = int(redirect)
     cnx = ndb.GetDBConnexion()
     groupEditor.edit(cnx, {"group_id": group_id, "group_name": group_name})
-
+    check_group_name(group_name, get_partition(group["partition_id"]), True)
     # redirect to partition edit page:
     if redirect:
         return flask.redirect(