diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index e283c977f5f..5678936ea5d 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -187,7 +187,7 @@ abstract class CommonObject
         $sql = "INSERT INTO ".MAIN_DB_PREFIX."element_contact";
         $sql.= " (element_id, fk_socpeople, datecreate, statut, fk_c_type_contact) ";
         $sql.= " VALUES (".$this->id.", ".$fk_socpeople." , " ;
-        $sql.= $this->db->idate($datecreate);
+        $sql.= "'".$this->db->idate($datecreate)."'";
         $sql.= ", 4, '". $id_type_contact . "' ";
         $sql.= ")";
         dol_syslog(get_class($this)."::add_contact sql=".$sql);