diff --git a/gazu/client.py b/gazu/client.py
index bb0275e4..b4e0f867 100644
--- a/gazu/client.py
+++ b/gazu/client.py
@@ -303,6 +303,30 @@ def delete(path, params=None, client=default_client):
     return response.text
 
 
+def get_message_from_response(response: requests.Request, default_message: str = "No additional information") -> str:
+    """
+    A utility function that handles Zou's inconsistent message keys.
+    For a given request, checks if any error messages or regular messages were given and returns their value.
+    If no messages are found, returns a default message.
+
+    Args:
+        response: requests.Request - A response to check.
+        default_message: str - An optional default value to revert to if no message is detected.
+
+    Returns:
+        The message of a given response, or a default message - if any.
+    """
+    message = default_message
+    message_json = response.json()
+
+    for key in ['error', 'message']:
+        if message_json.get(key):
+            message = message_json[key]
+            break
+
+    return message
+
+
 def check_status(request, path, client=None):
     """
     Raise an exception related to status code, if the status code does not
@@ -329,8 +353,7 @@ def check_status(request, path, client=None):
     elif status_code == 403:
         raise NotAllowedException(path)
     elif status_code == 400:
-        text = request.json().get("message", "No additional information")
-        raise ParameterException(path, text)
+        raise ParameterException(path, get_message_from_response(request))
     elif status_code == 405:
         raise MethodNotAllowedException(path)
     elif status_code == 413:
@@ -362,9 +385,8 @@ def check_status(request, path, client=None):
             stacktrace = request.json().get(
                 "stacktrace", "No stacktrace sent by the server"
             )
-            message = request.json().get(
-                "message", "No message sent by the server"
-            )
+            message = get_message_from_response(response=request,
+                                                default_message="No message sent by the server")
             print("A server error occured!\n")
             print("Server stacktrace:\n%s" % stacktrace)
             print("Error message:\n%s\n" % message)
@@ -474,8 +496,11 @@ def upload(path, file_path, data={}, extra_files=[], client=default_client):
     except JSONDecodeError:
         print(response.text)
         raise
-    if "message" in result:
-        raise UploadFailedException(result["message"])
+
+    result_message = get_message_from_response(response, default_message='')
+    if result_message:
+        raise UploadFailedException(result_message)
+
     return result
 
 
diff --git a/tests/test_client.py b/tests/test_client.py
index 5fdb6a9a..128f7ff4 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -1,5 +1,7 @@
 import datetime
 import json
+import random
+import string
 
 import unittest
 import requests_mock
@@ -281,19 +283,24 @@ def test_upload(self):
                     "./tests/fixtures/v1.png",
                     data={"test": True},
                 )
+
+            error_value = ''.join([random.choice(string.ascii_uppercase + string.ascii_lowercase) for _ in range(10)])
+
             with requests_mock.Mocker() as mock:
-                mock_route(
-                    mock,
-                    "POST",
-                    "data/new-file",
-                    text={"message": "Error"},
-                )
-                with self.assertRaises(gazu.client.UploadFailedException):
-                    raw.upload(
+                for field in ['message', 'error']:
+                    mock_route(
+                        mock,
+                        "POST",
                         "data/new-file",
-                        "./tests/fixtures/v1.png",
-                        data={"test": True},
-                    )
+                        text={field: error_value})
+
+                    with self.assertRaises(gazu.client.UploadFailedException) as context:
+                        raw.upload(
+                            "data/new-file",
+                            "./tests/fixtures/v1.png",
+                            data={"test": True})
+
+                    self.assertTrue(str(context.exception) == error_value)
 
     def test_upload_multiple_files(self):
         with open("./tests/fixtures/v1.png", "rb") as test_file:
diff --git a/tests/test_files.py b/tests/test_files.py
index 6319db21..bb44fbec 100644
--- a/tests/test_files.py
+++ b/tests/test_files.py
@@ -39,6 +39,16 @@ def test_new_working_file(self):
             )
             self.assertEqual(working_file["id"], 1)
 
+            mock.post(gazu.client.get_full_url(path),
+                      text=json.dumps({"error": "The given working file already exists."}),
+                      status_code=400)
+
+            with self.assertRaises(gazu.client.ParameterException) as context:
+                gazu.files.new_working_file(
+                    task, person={"id": "person-01"}, software={"id": "software-1"})
+
+                self.assertTrue(str(context.exception) == "The given working file already exists.")
+
     def test_new_entity_output_file(self):
         entity = {"id": "asset-01"}
         output_type = {"id": "output-type-01"}