diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d2b59ffda31d10d5693809ea9105c74c7e2564bf..87d65d5591a26341fecf9f5c8e2e77512a365b82 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -67,7 +67,7 @@ genassigns:
 frama-clang:
   stage: tests
   script:
-   - 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"
+   - nix/frama-ci.sh build -A frama-clang.tests
   tags:
    - nix
 
diff --git a/nix/default.nix b/nix/default.nix
index 889db9e1432856b4a338ca0f8cf396f8a62d162e..2066a81f8ee5c0a4589c6286eee8de3c18cd5df5 100644
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -234,7 +234,7 @@ rec {
            chmod -R u+w -- "$sourceRoot/src/plugins/counter-examples"
            cp -r --preserve=mode "$genassigns_src" "$sourceRoot/src/plugins/genassigns"
            chmod -R u+w -- "$sourceRoot/src/plugins/genassigns"
-           cp -r --preserve=mode "frama-clang_src" "$sourceRoot/src/plugins/frama-clang"
+           cp -r --preserve=mode "$frama-clang_src" "$sourceRoot/src/plugins/frama-clang"
            chmod -R u+w -- "$sourceRoot/src/plugins/frama-clang"
            cp -r --preserve=mode "$pathcrawler_src" "$sourceRoot/src/plugins/pathcrawler"
            chmod -R u+w -- "$sourceRoot/src/plugins/pathcrawler"