What do you have to be aware of in this traffic situation?

You answered correctly by choosing not to cross the lane marking. In German traffic rules, the solid white line on your side means you must not cross it. This marking indicates that overtaking or crossing the line to pass the vehicle ahead is prohibited, usually due to limited visibility or dangerous conditions. Even if the oncoming traffic seems far enough or permits it, you must respect the solid line to ensure safety. Crossing the line in such situations is not allowed. So, always follow the lane markings, especially solid lines, to prevent accidents on narrow or winding roads.