Where are you allowed to park on the left in the direction of travel?

You answered correctly. In Germany, you are allowed to park on the left side of the street in two situations: on one-way streets and on streets where there are rails (like tram tracks) on the right-hand side. This is allowed because it does not interfere with the normal flow of traffic. However, you cannot simply park on the left when parking is prohibited on the right. Instead, you must always follow the general parking rules for both sides of the road. Remembering these exceptions helps you recognize where parking on the left is legally permitted.