diff --git a/docs/ecolyo/functionalities/profile_type.md b/docs/ecolyo/functionalities/profile_type.md
index 065bb70fa3749f45e583ba0e909f4e44908167a8..4003506d65d32422ed54b980d98383076f00956a 100644
--- a/docs/ecolyo/functionalities/profile_type.md
+++ b/docs/ecolyo/functionalities/profile_type.md
@@ -110,3 +110,18 @@ Also, we consider that if the heating or the hotwater are collective, we don't c
 
 The method **fetchDJU(month:number)** tries to fetch the daily dju from the datagrandlyon API trough a remote doctype named _org.ecolyo.dju_.
 The data returned by this API are gathered by the lyon-bron-sta The API returns dju by day for a given month, so we add them to return a monthly dju. If remote doctype fails or return a null value, we returns instead the default dju stored in _heating.json_
+
+Usefull tips while working with this API :
+
+- Do not pass a Content-Type while requesting, it will returns error
+- While requesting from a cozy instance, if you get errors, you will get errors from the cozy stack and not directly from the API, which leads to weird cases :
+  - If there is an authentication error, the api will returns an error in _html_ format to cozy, so you'll get from cozy an error 502 as following, beacause cozy expects a json response :
+  ```json
+  {
+    "status": "502",
+    "title": "Bad Gateway",
+    "detail": "the content-type for the response is not authorized",
+    "source": {}
+  }
+  ```
+  - In case of bad request (wrong paramaters for example), the API will return an error in _xml_ format so you'll get exaclty the same error as above in your cozy instance.