diff --git a/.github/workflows/python_PR.yml b/.github/workflows/python_PR.yml
index 4893635..635bce0 100644
--- a/.github/workflows/python_PR.yml
+++ b/.github/workflows/python_PR.yml
@@ -46,10 +46,10 @@ jobs:
         pip install pykeops filtration-domination --upgrade
 
         if [[ ${{ matrix.os }} =~ "ubuntu-".* ]]; then
-          micromamba install cxx-compiler -c conda-forge
+          micromamba install cxx-compiler=1.6 -c conda-forge
         fi
         if [[ ${{ matrix.os }} =~ "windows-".* ]]; then
-          micromamba install cxx-compiler -c conda-forge
+          micromamba install cxx-compiler=1.6 -c conda-forge
         fi
 
     - name: Build package