diff --git a/sat/tools/common/data_format.py b/sat/tools/common/data_format.py
index e352380a..bc7eef6c 100644
--- a/sat/tools/common/data_format.py
+++ b/sat/tools/common/data_format.py
@@ -131,7 +131,7 @@ def serialise(data):
 
     @return(unicode): serialised data, can be transmitted as string to the bridge
     """
-    return json.dumps(data, ensure_ascii=False)
+    return json.dumps(data, ensure_ascii=False, default=unicode)
 
 def deserialise(serialised_data, default=None, type_check=dict):
     """Deserialize data from bridge