diff --git a/pkgs/by-name/de/devpi-client/package.nix b/pkgs/by-name/de/devpi-client/package.nix
index 73dc522b8bd7..109d2213eafe 100644
--- a/pkgs/by-name/de/devpi-client/package.nix
+++ b/pkgs/by-name/de/devpi-client/package.nix
@@ -60,7 +60,7 @@ python3.pkgs.buildPythonApplication (finalAttrs: {
     "--fast"
   ];
 
-  LC_ALL = "en_US.UTF-8";
+  env.LC_ALL = "en_US.UTF-8";
 
   __darwinAllowLocalNetworking = true;