Ensconced within a new 37-story apartment tower, the 60-room Kasa is designed for longer stays than a conventional hotel.

The sixth floor or attic space was reserved for servants. Nowadays, since the highest floor of a Haussmann-style apartment building promises sweeping views of the city’s rooftops, these ...

Mixed-use buildings can be as simple as a mom-and-pop retail shop in a storefront building with an apartment or two upstairs. Or it could be a single-family home with a doctor’s office on the ...