That's the NYC law, dating to pre-AirBnB times but now with new relevance. It distinguishes 'taking in a boarder' from 'subletting the apartment'. If you occupy

That's the NYC law, dating to pre-AirBnB times but now with new relevance. It distinguishes 'taking in a boarder' from 'subletting the apartment'. If you occupy the unit as your primary residence, you're allowed to take in boarders, defined as people with whom you intend to share the common spaces. So renting out a room in your apartment is fine (as long as you don't do some weird partitioning to make it de-facto a separate unit... you're supposed to be essentially welcoming a guest into your own household, even if it's a paid guest). But you can't do a whole-apartment sublet for periods shorter than 30 days.