We teach about the process of gentrification and segregation in sociology in most of our courses. Consulting is also busy with telling policy makers, urban planners and architects about this fundamental social process. A mathematical description of the process has been provided by Schelling as well. A recent striking depiction of the process evolving over years in Brussels is produced by Karim Douieb (dataViz and Jetpack, image below! and more, THANKS). The data is from the Brussels institute of statistics and analysis. Policy-makers have a hard time to work against the well-known tendency: birds of the same feather, gather together. Humans do not seem to be much different, at least when it comes to large metropolitan cities. Only a small China town is missing in Brussels.
What is masked in the grouping by nationalities of residents, is the underlying mechanisms that drive this gentrification. Even previously mixed parts of the city might suffer a slow process of erosion due to educational, job, wealth, poverty and housing differentiation between people and Brussels communities. Falling behind in educational achievement, then higher unemployment leads to lower credit worthiness and residence in less comfortable housing. The Belgian and EU15 residents are much more likely to follow virtuous upward mobility. Hence the process of gentrification trickles down through subsequent generations. Start with learning and socialising of kids and adult learning to overcome the discriminatory process. Ethnic communities will also have to open up to interact with locals. Social progress is hard work for all. 
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