diff --git a/pkgs/development/python-modules/rpmfluff/default.nix b/pkgs/development/python-modules/rpmfluff/default.nix
index 920b153b5577..c09407c9219f 100644
--- a/pkgs/development/python-modules/rpmfluff/default.nix
+++ b/pkgs/development/python-modules/rpmfluff/default.nix
@@ -15,7 +15,7 @@ buildPythonPackage rec {
     sha256 = "19vnlzma8b0aghdiixk0q3wc10y6306hsnic0qvswaaiki94fss1";
   };
 
-  LC_ALL = "en_US.utf-8";
+  env.LC_ALL = "en_US.utf-8";
   buildInputs = [ glibcLocales ];
 
   meta = {