Unable to answer "Who is allowed to park here? Parking may be free or paid." – Parking Lot – https://osm.org/way/935262841 via StreetComplete 59.3:

Da parken zwar Autos, aber die Beschilderung sagt Parkverbot.

Attached photo(s):
https://westnordost.de/p/251195.jpg
https://westnordost.de/p/251196.jpg