diff --git a/vas/rest/ws/vitis/File_downloader.class.inc b/vas/rest/ws/vitis/File_downloader.class.inc
index ad119c53ce1dc41670a75b01efe9005b92d55e65..202046917b9cd9caa1712b871c80ce1cd7006d30 100644
--- a/vas/rest/ws/vitis/File_downloader.class.inc
+++ b/vas/rest/ws/vitis/File_downloader.class.inc
@@ -130,7 +130,12 @@ class File_downloader extends Vitis {
             // modification de $sPath pour aller chercher le fichier dans ws_data
             $sPath = $this->aProperties["ws_data_dir"] . "/" . $this->aValues["key"];
             // check eTag
-            $bReturnFile = false;
+            $sEtag = sha1(file_get_contents($sPath), false);
+
+            if ($sEtag != $this->aValues['eTag']){
+              $bReturnFile = false;
+              $sMessage = array("status" => 0, "sMessage" => "This file doesn't exist or the Etag doesn't match");
+            }
           }
 
           if($bReturnFile){