diff --git a/src/agenda_culturel/calendar.py b/src/agenda_culturel/calendar.py
index 809d75c..f508eb0 100644
--- a/src/agenda_culturel/calendar.py
+++ b/src/agenda_culturel/calendar.py
@@ -58,14 +58,14 @@ class DayInCalendar:
 
     def is_ancestor_uuid_event_from_other(self, event):
         for e in self.events:
-            if event.is_ancestor_by_uuid(e):
+            if event.is_ancestor_by_uuid_and_rules(e):
                 return True
         return False
 
     def remove_event_with_ancestor_uuid_if_exists(self, event):
         removed = False
         for i, e in enumerate(self.events):
-            if e.is_ancestor_by_uuid(event):
+            if e.is_ancestor_by_uuid_and_rules(event):
                 # remove e from events_by_category
                 for k, v in self.events_by_category.items():
                     if e in v:
diff --git a/src/agenda_culturel/models.py b/src/agenda_culturel/models.py
index 9a9338b..44abc0d 100644
--- a/src/agenda_culturel/models.py
+++ b/src/agenda_culturel/models.py
@@ -2066,18 +2066,22 @@ class Event(models.Model):
             else:
                 return ":".join(els), 0
 
-    def is_ancestor_uuid(uuid1, uuid2):
+    def is_ancestor_uuid_and_rules(uuid1, uuid2, r1, r2):
         root1, version1 = Event.split_uuid(uuid1)
         root2, version2 = Event.split_uuid(uuid2)
-        return root1 == root2 and version1 < version2
+        return root1 == root2 and ((r1 and not r2) or (version1 < version2))
 
-    def is_ancestor_by_uuid(self, event):
+    def is_ancestor_by_uuid_and_rules(self, event):
         if self.uuids is None or event.uuids is None:
             return False
+        if (not self.recurrences) and event.recurrences:
+            return False
 
         for s_uuid in self.uuids:
             for e_uuid in event.uuids:
-                if Event.is_ancestor_uuid(s_uuid, e_uuid):
+                if Event.is_ancestor_uuid_and_rules(
+                    s_uuid, e_uuid, self.recurrences, event.recurrences
+                ):
                     return True
         return False