diff --git a/src/machi_file_proxy_sup.erl b/src/machi_file_proxy_sup.erl
index 639fa45..dbb0fa6 100644
--- a/src/machi_file_proxy_sup.erl
+++ b/src/machi_file_proxy_sup.erl
@@ -43,7 +43,7 @@ child_spec(FluName) ->
 start_link(FluName) ->
     supervisor:start_link({local, make_proxy_name(FluName)}, ?MODULE, []).
 
-start_proxy(FluName, Filename, DataDir) ->
+start_proxy(FluName, DataDir, Filename) ->
     supervisor:start_child(make_proxy_name(FluName), [Filename, DataDir]).
 
 init([]) ->