diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6d50bcc59527cf729a2b694f2c5d4fb27d2bb5f6..0211783ab95083ffba0bec80de1a4956f702fdbb 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -19,6 +19,6 @@ git-update:
 Tests:
   stage: tests
   script:
-   - nix/frama-ci.sh build -A frama-clang.tests
+   - nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/0c0fe6d85b92c4e992e314bd6f9943413af9a309.tar.gz -p nix --run "nix/frama-ci.sh build -A frama-clang.tests"
   tags:
    - nix