diff --git a/paris-container.nix b/paris-container.nix
index c052e6f..ffbba9c 100644
--- a/paris-container.nix
+++ b/paris-container.nix
@@ -7,7 +7,7 @@ let
   packages = with pkgs; [ rtorrent ];
 
 in {
-  options.fudo.paris-container = {
+  options.fudo.paris-container = with types; {
     enable = mkEnableOption "Enable Fudo Paris user server.";
 
     state-directory = mkOption {