What is allowed in the zone which starts here?

Your answer is fully correct.

This sign indicates a no-parking zone in Germany. Within this zone, stopping is only allowed for a short time: you can stop for up to 3 minutes or for specific purposes like loading, unloading, boarding, or alighting passengers. However, parking—meaning leaving a vehicle unattended for longer periods—is not permitted, even with a parking disc. This rule helps ensure traffic flow and prevents congestion in areas where parking would otherwise block or disrupt traffic.

Remember, stopping briefly (up to 3 minutes) or for essential activities related to loading or passenger movement is allowed, but leaving your vehicle parked here is not.