diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a361423bcc92f7dd7f52a03a99b43ffff836c51d..b665708adc74d74fc083cad7b495c02b069354ce 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -233,12 +233,12 @@ check-copyrights:
   script:
     - ./do-copyright.py
 
-clang-format:
+check-clang-format:
   image: corsika/devel:u-18.04
+  before_script:
+  - apt-get update && apt-get install -y -qq clang-format
   stage: optional
   tags:
     - corsika
   script:
     - ./do-clang-format.py --all
-
-