What are you talking about ? Are you even living in Germany? The rent prices here in Berlin are bonkers, landlords are asking 800 Euros warm for 35 sqm "flats" and they are able to get away with it because every flat in the area has at least 30+ applicants. Even if it is rent controlled and the contracts are illegal, you can not report it otherwise you get kicked and no other landlord will rent you their property. They literally ask you if you had any legal conflicts with your previous landlord and they can actually refuse your application because of this.
In my opinion, as ein verrückte britische Ausländer living in Berlin, the rent control is why so many people show up to flat viewings.
However, I think there is a lot of price variation in Berlin, and many cheap parts: I’m paying €485 for a room in a WG in Buchholz, while collecting €820 (after fees, at current exchange rates) from a flat in a quiet village 30 minutes away from Cambridge in the UK.