diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 53407da68615d2a24b5ec30c3dcfafd982e40fc7..d6684ba5597c17e2a14f6c578110dd54b5f185f6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -33,3 +33,11 @@ make_pdf:
   artifacts:
     paths:
       - "*.pdf"
+
+check_filesize:
+  allow_failure: true
+  script:
+    - echo 'Overview of file sizes for debugging:'
+    - find ./*.md -type f -exec du -a {} + | sort -n -r
+    # grep fails when du reports a file above the threshold
+    - du --threshold=-1MB *.md | grep -q ^