diff --git a/htdocs/fourn/facture/pre.inc.php b/htdocs/fourn/facture/pre.inc.php
index cc19f8a6f93..276e77f7664 100644
--- a/htdocs/fourn/facture/pre.inc.php
+++ b/htdocs/fourn/facture/pre.inc.php
@@ -28,7 +28,8 @@
 */
 
 require("../../main.inc.php");
-require(DOL_DOCUMENT_ROOT."/fournisseur.facture.class.php");
+require_once DOL_DOCUMENT_ROOT."/fournisseur.class.php";
+require_once DOL_DOCUMENT_ROOT."/fournisseur.facture.class.php";
 $user->getrights('fournisseur');
 
 function llxHeader($head = "", $title = "", $addons='') {