diff --git a/htdocs/supplier_proposal/class/supplier_proposal.class.php b/htdocs/supplier_proposal/class/supplier_proposal.class.php
index ecd940fea96..688f6aa1276 100644
--- a/htdocs/supplier_proposal/class/supplier_proposal.class.php
+++ b/htdocs/supplier_proposal/class/supplier_proposal.class.php
@@ -60,6 +60,9 @@ class SupplierProposal extends CommonObject
 	 */
 	public $table_element_line='supplier_proposaldet';
 
+	/**
+	 * @var int Field with ID of parent key if this field has a parent
+	 */
     public $fk_element='fk_supplier_proposal';
 
     public $picto='propal';
diff --git a/htdocs/user/class/user.class.php b/htdocs/user/class/user.class.php
index 97172214dc6..603c73fa33a 100644
--- a/htdocs/user/class/user.class.php
+++ b/htdocs/user/class/user.class.php
@@ -50,7 +50,11 @@ class User extends CommonObject
 	 */
 	public $table_element='user';
 
+	/**
+	 * @var int Field with ID of parent key if this field has a parent
+	 */
 	public $fk_element='fk_user';
+
 	public $ismultientitymanaged = 1;	// 0=No test on entity, 1=Test with field entity, 2=Test with link by societe
 
 	public $id=0;