diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 91beeff926f0a9d2e641fb79843e35abff30ddee..c8c53bb3a9456f2796f08f7c98a7dc2f6ad8a6d8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -539,6 +539,7 @@ Debian stable Clang:
 
   variables:
     CC: clang
+    CXX: clang
     WFLAGS: -Wno-cast-align -Wno-implicit-const-int-float-conversion -Werror
     CFLAGS: -Wno-cast-align -Wno-implicit-const-int-float-conversion -Werror
     LDFLAGS: -Wl,-fuse-ld=gold
@@ -594,6 +595,7 @@ Debian testing Clang:
 
   variables:
     CC: clang
+    CXX: clang
     WFLAGS: -Wno-cast-align -Wno-implicit-const-int-float-conversion -Werror -Wno-deprecated-non-prototype -Wno-single-bit-bitfield-constant-conversion
     CFLAGS: -Wno-cast-align -Wno-implicit-const-int-float-conversion -Werror -Wno-deprecated-non-prototype -Wno-single-bit-bitfield-constant-conversion
     LDFLAGS: -Wl,-fuse-ld=gold