diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index abc83ea4f99c..6d380d480e3a 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -19862,7 +19862,11 @@ in
 
   fractal = callPackage ../applications/networking/instant-messengers/fractal { };
 
-  freecad = qt5.callPackage ../applications/graphics/freecad { mpi = openmpi; };
+  freecad = qt5.callPackage ../applications/graphics/freecad {
+    mpi = openmpi;
+    # pyside2 5.12 is broken under python 3.8
+    python3Packages = python37Packages;
+  };
 
   freemind = callPackage ../applications/misc/freemind { };