Unfortunately it means it's extremely hard to live in Paris if you're middle class. If you're upper middle class/rich, you can rent/buy. If you're poor, you get a chance to get public housing. If you're middle class, too bad for you.
I'm middle class and lived in Paris. I had rich friends and poor friends. My rich friends owned flats that occupied entire floors of a building. My poor friends got whatever social housing was available. And my middle class friends rented or bought a place in the suburbs with more space. We owned, a relatively small by American standards 55sqm, 3F, flat in the city center. My middle class friends could also rent the…
You'd be hard pressed to even find this outside of a few areas in NYC.