Earlier quoted context omitted.
I'm not convinced. I live in Berlin and everyone is living in a flat, yet I've had my fair share of home parties, even in small two room apartments where half the party spilled out to the stairwell.
I don't think Berlin is a good example because partying is kind of part of the city subculture. People travel there literally to party.
Partying in someone's apartment is a thing in probably every reasonably sized city in Europe, not just Berlin. Although you should probably alert your neighbours.