Chinese residential city blocks aren’t any denser than American ones, they do have more green space though. Paris is one of the densest cities in the world and it doesn’t really get taller than eight stories high.
Levallois-Perret is a commune bordering on central Paris, and a comparable size to a single arrondissement (subdivision within Paris proper). For example, the 11th arrondissement [1] is 50% larger and 100% denser than Levallois-Perret. But it doesn't count because it isn't it's own separate administrative area.
All this to say: the closer you look, the harder it is to rank places by population density. The comment point was that high population density can be reaching without high rises.
Aren’t Parisian apartments also really small? I’m in a 90 sq m two-bedroom in Seattle and I shudder to think what I’d have to pay in central Paris for that.
For the record, it is 24th in the world:
* https://en.wikipedia.org/wiki/List_of_cities_by_population_d...
And there are other French cities above it: Levallois-Perret is 8th at 26,432/km^2.