diff --git a/mycaldav/models.py b/mycaldav/models.py
index 6807b59..69311c0 100644
--- a/mycaldav/models.py
+++ b/mycaldav/models.py
@@ -169,7 +169,9 @@ class cls_caldav_client():
          #   print(event.vobject_instance.vevent.eventId)
     def mark_as_done_task(self,calandar,uuid):
         event = self.get_event_by_uuid(calandar=calandar,uuid=uuid)
-        event.vobject_instance.vevent.description.value = event.vobject_instance.vevent.description.value + " #Fait"
+        if "#Fait" not in event.vobject_instance.vevent.description.value:
+            event.vobject_instance.vevent.description.value = event.vobject_instance.vevent.description.value + " #Fait"
+
         event.save()