diff --git a/nix/treefmt/flake-module.nix b/nix/treefmt/flake-module.nix
index 34ed88d..258a0e7 100644
--- a/nix/treefmt/flake-module.nix
+++ b/nix/treefmt/flake-module.nix
@@ -18,7 +18,7 @@
           "-eucx"
           ''
             ${pkgs.ruff}/bin/ruff --fix "$@"
-            ${pkgs.python3.pkgs.black}/bin/black "$@"
+            ${pkgs.ruff}/bin/ruff format "$@"
           ''
           "--" # this argument is ignored by bash
         ];