diff --git a/htdocs/compta/sociales/class/chargesociales.class.php b/htdocs/compta/sociales/class/chargesociales.class.php
index c0aac835bba..05169adcf7b 100644
--- a/htdocs/compta/sociales/class/chargesociales.class.php
+++ b/htdocs/compta/sociales/class/chargesociales.class.php
@@ -317,7 +317,7 @@ class ChargeSociales extends CommonObject
         $sql.= ", date_ech='".$this->db->idate($this->date_ech)."'";
         $sql.= ", periode='".$this->db->idate($this->periode)."'";
         $sql.= ", amount='".price2num($this->amount, 'MT')."'";
-		$sql.= ", fk_projet='".($this->fk_project > 0 ? $this->db->escape($this->fk_project) : NULL)."'";
+		$sql.= ", fk_projet='".($this->fk_project > 0 ? $this->db->escape($this->fk_project) : null)."'";
         $sql.= ", fk_user_modif=".$user->id;
         $sql.= " WHERE rowid=".$this->id;