diff --git a/redhat/applications/k3b/k3b-14.0.0.spec b/redhat/applications/k3b/k3b-14.0.0.spec
index 4a4eee1c1..a83b551bc 100644
--- a/redhat/applications/k3b/k3b-14.0.0.spec
+++ b/redhat/applications/k3b/k3b-14.0.0.spec
@@ -430,7 +430,7 @@ export PKG_CONFIG_PATH="%{tde_libdir}/pkgconfig:${PKG_CONFIG_PATH}"
 
 # FFMPEG trick ...
 if [ -d /usr/include/ffmpeg ]; then
-	export CXXFLAGS="${RPM_OPT_FLAGS} -I/usr/include/ffmpeg"
+	export RPM_OPT_FLAGS="${RPM_OPT_FLAGS} -I/usr/include/ffmpeg"
 fi
 
 if ! rpm -E %%cmake|grep -q "cd build"; then