[looki]

Even the (by far) most dense borough of Berlin is only at 14,373/km²[1], though. That's considerably lower than almost all of the Parisian boroughs[2]. Even the whole city's average is 20,000/km². From the point of view of most American cities with some obvious exceptions, the difference is probably indeed not that noticeable though.

[1] https://de.wikipedia.org/wiki/Verwaltungsgliederung_Berlins

[2] https://en.wikipedia.org/wiki/Arrondissements_of_Paris