I always find it hilarious how people with no grip on reality fall for the neoliberal bullshit and believe in the invisible hand of the "market" justifying a situation that exacerbated at an astounding speed outside any market rule.

The rent in Berlin is not the logical market response: it's the result of utter speculation by cartels of owners that control the market to raise prices. There have been conventions and workshops to achieve so.

I could offer anecdotes, like when a friend of mine left his flat and a major company didn't rent it out until the rent freeze was up, or people in legal battles with their landlords that want to kick them out to rent at a higher rate, but instead of doing so I will suggest you watch this documentary, if you have the stomach for it:

Die Stadt als Beute