Yes, this happens, mostly between private landlords (of which Germany has a lot) and tenants of (seemingly or actually) limited legal competence (because privat

Yes, this happens, mostly between private landlords (of which Germany has a lot) and tenants of (seemingly or actually) limited legal competence (because private tenants are in fact relatively well-protected by law except for some gaping loopholes ("Eigenbedarf" being the most-exploited one), but of course accessing that protection often means they have to go to court first, which is a considerable financial and cognitive bar not everyone is able to jump over). I am not sure if it's more often than in other European countries, because I refuse to believe it doesn't happen there as well. You have a large difference in power, it gets exploited, one way or the other way round.