diff --git a/htdocs/compta/bank/account_statement_document.php b/htdocs/compta/bank/account_statement_document.php
index 26613a6bb49..9585ac55973 100644
--- a/htdocs/compta/bank/account_statement_document.php
+++ b/htdocs/compta/bank/account_statement_document.php
@@ -130,7 +130,7 @@ if (!empty($numref)) {
 	$object->fetch_thirdparty();
 	$upload_dir = $conf->bank->dir_output."/".$id."/statement/".dol_sanitizeFileName($numref);
 }
-$backtopage = $_SERVER['PHP_SELF']."?account=".urlencode($id)."&num=".urlencode($numref);
+$backtopage = $_SERVER['PHP_SELF']."?account=".urlencode((string) ($id))."&num=".urlencode((string) ($numref));
 include DOL_DOCUMENT_ROOT.'/core/actions_linkedfiles.inc.php';