diff --git a/IM/REST.py b/IM/REST.py
index 1a6720578..742b1fac2 100644
--- a/IM/REST.py
+++ b/IM/REST.py
@@ -284,7 +284,7 @@ def format_output(res, default_type="text/plain", field_name=None, list_field_na
                     if isinstance(res, list):
                         info = "\n".join(res)
                     else:
-                        info = str(res)
+                        info = "%s" % res
                 content_type = default_type
                 break
 
@@ -299,7 +299,7 @@ def format_output(res, default_type="text/plain", field_name=None, list_field_na
             if isinstance(res, list):
                 info = "\n".join(res)
             else:
-                info = str(res)
+                info = "%s" % res
         bottle.response.content_type = default_type
 
     return info
diff --git a/test/unit/REST.py b/test/unit/REST.py
index 0520aa01a..a6f8ab1db 100755
--- a/test/unit/REST.py
+++ b/test/unit/REST.py
@@ -778,6 +778,9 @@ def test_format_output(self, get_media_type):
         info = format_output(["1", "2"])
         self.assertEqual(info, '1\n2')
 
+        info = format_output(u'contmsg\xe1', field_name="contmsg", default_type="text/plain")
+        self.assertEqual(info, u'contmsg\xe1')
+
         get_media_type.return_value = ["application/zip"]
         info = format_output(["1", "2"])
         self.assertEqual(info, 'Unsupported Accept Media Types: application/zip')