diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bde670a852e46baa6c628c3a150cce6a2f9bd2fb..0606bad0c0ce1af6a7e76afc832df41b91f918dd 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -34,7 +34,7 @@ build-coq.8.15.1:
   <<: *template
   variables:
     OPAM_PINS: "coq version 8.15.1"
-    #DENY_WARNINGS: "1"
+    DENY_WARNINGS: "1"
     #MANGLE_NAMES: "1"
     #OPAM_PKG: "1"