diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index af197c9250e6d1ede4cf3609cf93bb3d66d091a8..469c5a943a4301580097d4942c71c63e83c81999 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -16,8 +16,8 @@ docs:userguide:
   image: sphinxdoc/sphinx:latest
   script:
     - pip install -q sphinx_rtd_theme sphinx_tabs sphinxcontrib-bibtex
-    - sphinx-build -b html docs/source_docs/ build/docs
-    - sphinx-build -b html docs/picvva/ build/picvva
+    - sphinx-build -W -b html docs/source_docs/ build/docs
+    - sphinx-build -W -b html docs/picvva/ build/picvva
   stage: build-docs
   artifacts:
     name: $CI_JOB_NAME