diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index ae094b4469c..3cec41d721e 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -659,7 +659,7 @@ class Lead(FormatAddress, models.Model):
     def _get_duplicated_leads_by_emails(self, partner_id, email, include_lost=False):
         """ Search for opportunities that have the same partner and that arent done or cancelled """
         if not email:
-            return []
+            return self.env['crm.lead']
         partner_match_domain = []
         for email in set(email_split(email) + [email]):
             partner_match_domain.append(('email_from', '=ilike', email))