diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index 9d1800af742..51a72d6beb2 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -550,7 +550,7 @@ abstract class CommonObject
 			dol_print_error(get_class()."::isExistingObject ".$error, LOG_ERR);
 			return -1;
 		}
-		if ($ref || $ref_ext) {
+		if ($ref || $ref_ext) {		// Because the same ref can exists in 2 different entities, we force the current one in priority
 			$sql .= " AND entity = ".((int) $conf->entity);
 		}