diff --git a/addons/event/event.py b/addons/event/event.py
index 4d035d8a2d2..42ed73fc055 100644
--- a/addons/event/event.py
+++ b/addons/event/event.py
@@ -245,7 +245,7 @@ class event_event(models.Model):
         return res
 
     @api.one
-    def mail_attendees(self, template_id, force_send=True, filter_func=lambda self: True):
+    def mail_attendees(self, template_id, force_send=False, filter_func=lambda self: True):
         for attendee in self.registration_ids.filtered(filter_func):
             self.env['mail.template'].browse(template_id).send_mail(attendee.id, force_send=force_send)