diff --git a/addons/base_calendar/base_calendar.py b/addons/base_calendar/base_calendar.py
index 88ee1a8ec33..722ac5cb0a8 100644
--- a/addons/base_calendar/base_calendar.py
+++ b/addons/base_calendar/base_calendar.py
@@ -1065,7 +1065,7 @@ class calendar_event(osv.osv):
             'rule_type': rrule_type,
             'id': id,
         })
-        cr.execute(qry, val) # Hopefully psycopg2 works with dicts. But, FIXME
+        cr.execute(qry % val)
         return True
 
     def _get_rulestring(self, cr, uid, ids, name, arg, context=None):