diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 03eeaa9d6ad3da096455f3ae0ec8abc87743f590..5d91188d616703bc3a27d3cc2d9c2dbb45b26fb5 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -41,6 +41,7 @@ make_doc:
     stage: test
     script:
         - cd build
+        - export LC_CTYPE=en_US.UTF-8
         - make doc
     artifacts:
         paths: