diff --git a/src/agenda_culturel/models.py b/src/agenda_culturel/models.py
index 194d36a..4a4b5d7 100644
--- a/src/agenda_culturel/models.py
+++ b/src/agenda_culturel/models.py
@@ -245,13 +245,19 @@ class Event(models.Model):
         self.local_image = File(name=basename, file=open(tmpfile, "rb"))
 
 
+    def is_in_importation_process(self):
+        return hasattr(self, "in_importation_process")
+
+    def set_in_importation_process(self):
+        self.in_importation_process = True
+
     def update_dates(self):
         now = timezone.now()
         if not self.id:
             self.created_date = now
-        if hasattr(self, "require_imported_date"):
+        if self.is_in_importation_process():
             self.imported_date = now
-        if not hasattr(self, "require_imported_date") or self.modified_date is None:
+        if self.is_in_importation_process() or self.modified_date is None:
             self.modified_date = now
 
 
@@ -267,8 +273,18 @@ class Event(models.Model):
 
         self.prepare_save()
 
-        # delete duplicated group if it's only with one element
-        if self.possibly_duplicated is not None and self.possibly_duplicated.nb_duplicated() == 1:
+        # check for similar events if no duplicated is known
+        if self.possibly_duplicated is None:
+            # and if this is not an importation process
+            if not self.is_in_importation_process():
+                similar_events = self.find_similar_events()
+
+                # if it exists similar events, add this relation to the event
+                if len(similar_events) != 0:
+                    self.set_possibly_duplicated(similar_events)
+
+        elif self.possibly_duplicated is not None and self.possibly_duplicated.nb_duplicated() == 1:
+            # delete duplicated group if it's only with one element
             self.possibly_duplicated.delete()
             self.possibly_duplicated = None
 
@@ -408,7 +424,7 @@ class Event(models.Model):
         # for each event, check if it's a new one, or a one to be updated
         for event in events:
             # imported events should be updated
-            event.require_imported_date = True
+            event.set_in_importation_process()
             event.prepare_save()
 
             # check if the event has already be imported (using uuid)
@@ -421,7 +437,7 @@ class Event(models.Model):
                 if same_imported:
                     # if this event exists, it will be updated with new data
                     same_imported.update(event)
-                    same_imported.require_imported_date = True
+                    same_imported.set_in_importation_process()
                     same_imported.prepare_save()
                     to_update.append(same_imported)
                 else:
@@ -441,7 +457,7 @@ class Event(models.Model):
                     if same_events is not None and len(same_events) > 0:
                         # merge with the first one
                         same_events[0].update(event)
-                        same_events[0].require_imported_date = True
+                        same_events[0].set_in_importation_process()
                         same_events[0].prepare_save()
                         to_update.append(same_events[0])
                     else: