diff --git a/src/libcharon/plugins/vici/python/vici/session.py b/src/libcharon/plugins/vici/python/vici/session.py
index 0d6ee9b65..0a2a02f91 100644
--- a/src/libcharon/plugins/vici/python/vici/session.py
+++ b/src/libcharon/plugins/vici/python/vici/session.py
@@ -78,7 +78,7 @@ class Session(CommandWrappers, object):
             if command_response["success"] != b"yes":
                 raise CommandException(
                     "Command failed: {errmsg}".format(
-                        errmsg=command_response["errmsg"]
+                        errmsg=command_response["errmsg"].decode("UTF-8")
                     )
                 )
 
@@ -135,7 +135,7 @@ class Session(CommandWrappers, object):
             if command_response["success"] != b"yes":
                 raise CommandException(
                     "Command failed: {errmsg}".format(
-                        errmsg=command_response["errmsg"]
+                        errmsg=command_response["errmsg"].decode("UTF-8")
                     )
                 )