diff --git a/pkgs/development/python-modules/cssselect2/default.nix b/pkgs/development/python-modules/cssselect2/default.nix
index 9d30ec093121..987e84ffcee2 100644
--- a/pkgs/development/python-modules/cssselect2/default.nix
+++ b/pkgs/development/python-modules/cssselect2/default.nix
@@ -1,5 +1,6 @@
 { lib
 , buildPythonPackage
+, flit-core
 , pythonOlder
 , fetchPypi
 , tinycss2
@@ -9,6 +10,7 @@
 buildPythonPackage rec {
   pname = "cssselect2";
   version = "0.5.0";
+  format = "pyproject";
   disabled = pythonOlder "3.5";
 
   src = fetchPypi {
@@ -20,6 +22,10 @@ buildPythonPackage rec {
     sed -i '/^addopts/d' pyproject.toml
   '';
 
+  nativeBuildInputs = [
+    flit-core
+  ];
+
   propagatedBuildInputs = [ tinycss2 ];
 
   checkInputs = [ pytestCheckHook ];