diff --git a/CHANGELOG b/CHANGELOG
index d78739e40b..58bc69dc54 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,4 @@
+* Return 400 instead of 500 for Tryton exception
 * Fill the reverse field in the One2Many setter
 * Drop support for skiptest attribute on xml files
 * Remove implicit field names in ModelStorage.search_read
diff --git a/trytond/protocols/jsonrpc.py b/trytond/protocols/jsonrpc.py
index 3f03a3aaea..7c876da521 100644
--- a/trytond/protocols/jsonrpc.py
+++ b/trytond/protocols/jsonrpc.py
@@ -153,7 +153,9 @@ class JSONProtocol:
             else:
                 response['result'] = data
         else:
-            if isinstance(data, Exception):
+            if isinstance(data, TrytonException):
+                return BadRequest(data)
+            elif isinstance(data, Exception):
                 return InternalServerError(data)
             response = data
         return Response(json.dumps(
diff --git a/trytond/protocols/xmlrpc.py b/trytond/protocols/xmlrpc.py
index f2a35e64d1..0a238a3412 100644
--- a/trytond/protocols/xmlrpc.py
+++ b/trytond/protocols/xmlrpc.py
@@ -153,6 +153,8 @@ class XMLProtocol:
                     data, methodresponse=True, allow_none=True),
                 content_type='text/xml')
         else:
-            if isinstance(data, Exception):
+            if isinstance(data, TrytonException):
+                return BadRequest(data)
+            elif isinstance(data, Exception):
                 return InternalServerError(data)
             return Response(data)