French, Chinese and Nigerian are nationalities, not races. If you think China is ethnically homogeneous, you're quite wrong. Just look at a linguistic map: https://upload.wikimedia.org/wikipedia/commons/5/55/China_li... The government does classify 90% of the population as a single group "Han", but that's partially a political move to discourage local separatism. Despite increased mixture between regions since the introduction of faster transportation, cultural differences are still visible, such as northerners eating more noodles, while southerners eat more rice.

> northerners eating more noodles, while southerners eat more rice.

You don't have to look that closely to find diversity in Paris.