I remember Hollandtown, little Italy, Greektown, and other areas in the city I grew up near. But nobody even hinted they were forced to live there.
Walking up Manhatten's East Side when I went to school in Jersey, it was the same. Every few blocks a different ethnicity dominated. Later, Brighton Beach was apparently where the Clinton administration required Russian immigrants to live; or perhaps it's where a lot of immigrants decided to move. So hard to tell an emergent distribution from a mandated outcome, I guess.
In LA, I lived in what used to be little Japan before FDR ordered them all to Manzanita. Some returned to their former digs, but the area was mostly non-Japanese in the '90s. But there was the Korean part of town, the Vietnamese area down in Orange County, etc., etc.
Similarly, I know the Indo-Pak area of Houston, little Korea, the Mexican and "other central American" sections, the black areas of Houston, a nifty little Vietnamese area. But there's nothing institutional about them. If you don't speak English, you want to be around those who speak your language. You like those of your own culture and religion. You like being around stores that sell "your" food. And since families often immigrated, and sometimes villages, you wanted to be around people you know.
Americans did this in Prague in the '90s. It's human.