diff --git a/contrib/docker/docker-compose.yaml b/contrib/docker/docker-compose.yaml
index b8517f70..27a6a7c9 100644
--- a/contrib/docker/docker-compose.yaml
+++ b/contrib/docker/docker-compose.yaml
@@ -33,6 +33,7 @@ services:
       TURN_USER: "${TURN_USER}"
       TURN_PASSWORD: "${TURN_PASSWORD}"
       START_ROOM_URL: "${START_ROOM_URL}"
+      FALLBACK_LOCALE: "${DEFAULT_LOCALE}"
     labels:
       - "traefik.http.routers.front.rule=Host(`play.${DOMAIN}`)"
       - "traefik.http.routers.front.entryPoints=web"