Sorry, but you have no idea what you're talking about. The "swift" solution would send you to jail in mere hours. You're presumed guilty. Yes, it defies any logic, but that's the way that it is.
My mom's husband had rented his previous flat (to complement his pension) to two women. They were working, very "normal" persons, and the contract specified that no other person could live there. One of them started dating a man and, a year later, there were three, then four (a child) living there. Then the other woman left (the guy was violent) and then the mother and her child had to flee too.
So my mom's husband had a guy that he never had any agreement with, living in his property, not paying rent, and not paying utilities. Now the law forbids to cut the utilities so you have to pay utilities for him. I think at the time (five years ago) it was still possible to cut. But the guy didn't care. After a year and a hell in courts, the flat was free again but a complete mess, broken furniture, mountains of junk. To weeks were needed just to clean, then paint, fixing doors, plumbing, etc.
He sold it ASAP. Now, I don't wonder why there's so little housing for rent.