diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 3e752de..6e5d3ce 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -72,9 +72,9 @@ push_docker:
 .docs:
   image: "${CI_REGISTRY_IMAGE}:dev"
   before_script:
-    - pip install -r docs/requirements.txt
+    - pip install -r requirements.txt -r docs/requirements.txt
   script:
-    - (cd docs && make)
+    - (cd docs && SPHINXARGS='-W' make)
     - mv docs/html public
   artifacts:
     paths:
diff --git a/docs/Makefile b/docs/Makefile
index 8d03407..6add764 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -10,7 +10,7 @@ clean:
 	rm -rf html source/cli .buildinfo .doctrees
 
 html:
-	sphinx-build $(buildargs)
+	sphinx-build $(SPHINXARGS) $(buildargs)
 
 serve: html
 	(cd html && python -m http.server 9999)