diff --git a/grandlyon_cartads_cs/models.py b/grandlyon_cartads_cs/models.py
index a029318..34e24bd 100644
--- a/grandlyon_cartads_cs/models.py
+++ b/grandlyon_cartads_cs/models.py
@@ -89,3 +89,6 @@ class GLCartaDSCS(AbstractCartaDSCS):
                     }
                     )
             resp.raise_for_status()
+            if resp.content:
+                # error messages are put in content, valid responses are empty.
+                raise Exception(resp.content)