I'm sure most people on here realize this, but European cities are the opposite of US cities - poor people live in suburbs outside the city, living in the city is desirable.
If you think the debate over gentrification is interesting now, just imagine what it will look like in US cities where this flip-flop takes place.
I live in the Twin Cities, MN, and see this happening to Minneapolis-St Paul as they seem to be going through this right now