diff --git a/lib/services/ngsi/entities-NGSI-v2.js b/lib/services/ngsi/entities-NGSI-v2.js
index ec83729b5..4a0d89460 100644
--- a/lib/services/ngsi/entities-NGSI-v2.js
+++ b/lib/services/ngsi/entities-NGSI-v2.js
@@ -273,7 +273,8 @@ function sendUpdateValueNgsi2(entityName, originMeasures, originTypeInformation,
             return initObj;
         }
     }
-    //it returns a flat object from an Metadata Object
+    //it returns a metadata object using the same structure described
+    // at https://github.com/telefonicaid/fiware-orion/blob/master/doc/manuals/orion-api.md#metadata-support
     function reduceMetadataAttrToPlainObject(attrs, initObj = {}) {
         if (attrs !== undefined && Array.isArray(attrs)) {
             return attrs.reduce((result, item) => {