Europe does not have this problem.
As a consequence, Europe's cities, which got much more populous in the 19th Century, stayed populated with a working population and huge suburbs did not get created after WWII. Immigrants and the poor were shunted into housing estates outside the city core, which is why the most depressed areas around Paris and London are mostly on the periphery.
In Germany they allowed poor immigrant workers and now migrants to cluster in certain neighborhoods, which is why Berlin now has areas that look like American slums. Deindustrialization, easy access to drugs and soaring rents have also given Berlin a large homeless population as well.
European cities lost an lot of their medieval and early modern heritage in the 19th century when a lot of medieval buildings & fortifications were torn down.