diff --git a/docker-compose.yml b/docker-compose.yml
index 99cb09a..6d5e8d5 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -24,6 +24,7 @@ services:
       POSTGRES_USER: ${POSTGRES_USER:-synapse}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
       PGDATA: /var/lib/postgresql/data/pgdata
+      POSTGRES_INITDB_ARGS: "--locale=C --encoding=UTF8"
     volumes:
       - ./postgres_data:/var/lib/postgresql/data