diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index 22c943dfa6e..5f290900de8 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -330,7 +330,9 @@ class Product extends CommonObject
      */
     public $date_creation;
 
-
+    /**
+     * @var integer|string date_modification
+     */
     public $date_modification;
 
     //! Id du fournisseur