diff --git a/addons/crm/crm_lead.py b/addons/crm/crm_lead.py
index 6e8e966f5b0..9d17526c19f 100644
--- a/addons/crm/crm_lead.py
+++ b/addons/crm/crm_lead.py
@@ -636,7 +636,7 @@ class crm_lead(format_address, osv.osv):
         # Merge notifications about loss of information
         opportunities = [highest]
         opportunities.extend(opportunities_rest)
-        self._merge_notify(cr, uid, highest, opportunities, context=context)
+        self._merge_notify(cr, uid, highest.id, opportunities, context=context)
         # Check if the stage is in the stages of the sales team. If not, assign the stage with the lowest sequence
         if merged_data.get('section_id'):
             section_stage_ids = self.pool.get('crm.case.stage').search(cr, uid, [('section_ids', 'in', merged_data['section_id']), ('type', '=', merged_data.get('type'))], order='sequence', context=context)