> Living in shared flats is very common in Germany presumably most of Europe.

It's common in the United States, too.

This is one of those weird laws that's on the books but is almost never enforced.

Any college town will have houses full of college students. In my experience, the only enforcement actions were when landlords were renting out houses to more people than they had rooms, so they had situations where one person was living in a closet or an attic or other space that doesn't have proper fire egress. They don't mess around with that once it's discovered.

> This is one of those weird laws that's on the books but is almost never enforced.

Let me introduce to the concept of rubber laws, a beloved tool of every totalitarian states. I now pass over to GPT:

“Rubber laws are vague catch-all offenses—like old vagrancy or ‘disorderly conduct’ laws on steroids. Because they’re so unclear, authorities can always say you broke one, and they use that flexibility to target inconvenient people. In the U.S., the Supreme Court generally strikes down such vague laws under the void-for-vagueness doctrine—but authoritarian systems keep them precisely because vagueness makes selective enforcement easy.”