Where is it forbidden to stop?

You answered correctly. It is forbidden to stop on merging and demerging lanes, as well as on lanes marked with direction arrows. These areas must remain clear to ensure smooth and safe traffic flow, prevent obstruction, and allow vehicles to merge or change direction without hindrance. Stopping in such places can create dangerous situations and is therefore not allowed by German traffic rules. However, stopping directly in front of property entrances and exits is only prohibited if it blocks access. In general, always avoid stopping where it could endanger or inconvenience other road users.