Where are you allowed to park a trailer with a permissible total mass exceeding 2 t in built-up areas regularly on sundays and public holidays and between 10 p.m. and 6 a.m.?

Your answer is correct. According to German traffic rules, trailers with a permissible total mass exceeding 2 tons are subject to specific parking restrictions in built-up areas during certain times, such as Sundays, public holidays, and nighttime (10 p.m. to 6 a.m.). They may be parked regularly only in industrial areas and in wholly residential areas, but in residential areas only on specially designated parking spaces. This is to prevent obstruction and ensure safety and convenience for other road users. Parking in special recreational areas or on standard roads is not permitted for such heavy trailers during these times. Understanding this helps you comply with parking regulations aimed at minimizing disturbances in sensitive or crowded areas.