On the release of The Sims 3 Late Night, sims will beable to live in apartments, but not like in The Sims 2 Apartment life, it's more dumb down but is more based on the views then anything else as SimGuruNita has explained:
Following the announcement of The Sims 3 Late Night, there are some questions arise about living in apartments. SimGuruWalrus explain how exactly this is.
We do not have apartments in the same way Apartment Life had an apartment. Your Sims are able to live in high rise like structures, some luxurious, some a bit more middle class. In them, your Sims are limited in how and where they can build (like an apartment). There’s a lobby downstairs with a callbox and elevator. You may see other Sims move in and out, but your active Sims are the ONLY ones who really live there.
We focused on the coolest part of living in an apartment – the view, the limited space, the elevator entrance, but do not have complex gameplay built around communal living.