diff --git a/README.md b/README.md
index 4c7104d259cab899652b69cd2deb4948ce936e4f..565e3ccf11ea71a23258f59898fa1d7ff24289de 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ After a collegue has made changes, then locally:
 
 ### Postgres Database in Docker
 
-Run `docker-compose up -d` with the following compose file to spin up a new Postgres container.
+Run `docker-compose -f docker-compose-postgres-dev.yml up -d` with the following compose file to spin up a new Postgres container.
 See the `docker-compose-postgres-dev.yml` file in the `docker` directory.
 (not that port 5433 is used. You can change that at will, but then also change it in `dev.py`)
 ```yaml