Rental Laws (code)---My landlord does not allow my firends stay overnight?

Rental Laws (code)---My landlord does not allow my firends stay overnight?
I live in NYC, the rented unit is a three bedroom appartment, recently I receive a letter form my landlord.
She states on the letter that due to the contract "the rented unit will be only occupied by three preson(s) otherwise the tenant will be charged an additional $100 for per additional person. So from the next month the tenants need to pay additional $200 rental fee".
The moral of the story is that, one of my housemate and me bring our girl friends back home regularly and they will stay overnight approximately 2-4 times a week. This situation noticed by the landlord several times, so she now wants us to pay $200 more per month.

Is this a legal action for a landlord?
How to interpret the term "occupied by no more than three person(s)"

Thank you for your time

The law (McKinney's New York Real Property Law 搂235-f) is clear that a lease to a person (or several people) permits occupancy by the persons on the lease, their immediate family (spouse, children, parents) and one more person.
Do not pay the rent. Let her try to evict you. She will be laughed out of court.

As a landlord, occupancy is generally a stipulation in the lease agreement.

I've only ever owned single family dwelling and checked my properties at rent time especially if I was receiving rent late.

Your land lord is in the right.. If it becomes such that 3 occupants become 6 occupants they can be ticketed for fire code violations the letter is their way of reminding you the stipulations of your lease so they don't get fined.

Here in the mid west we have those clauses in our lease agreements as well.. I know of one friend who owns properties in our city's Little Mexico he had to stipulate no more then 2 adults and direct dependent children. These keeps moving in 30 family members in to his house and wind up losing his property because repairs.

Not lawful. A landlord has no legal right to prescribe who may or may not visit, or how long they may stay. Nor can a lease impose any charge for such. Check with your local tenant's association, or the apartment owner's association, for particulars.
Postscript: pervious response is worth reading carefully.

I think you're screwed; but talk to zoning in your county for what the difference between "occupied" and "playing hide the salami with" are. Your salvation may lie in what your county calls "Occupied"; verses the "residing" test

I am not sure how NY defines occupancy but it in Texas a person has to live there in order to be called an occupant. A visitor is not an occupant. I would not pay the extra rent. It would be her burden to prove that in court.

I don't know what the exact definition of "occupied" is in this case, but crap like this is the reason I finally decided to buy a place. I've dealt with too much nonsense like this in the past when renting.

If those friend have a separate place, where they pay rent, and recieve mail, tell your landlord to get stuffed.

David S. is correct. The landlord can otherwise raise rents, but for that reason she can not.

sounds legal to me

I took wizjp to takes over an answer pretty hard the other day, so it is only fair to note my glee with his word play ijn his/her answer to this question. fair is fair :)

from the landlord's point of view, the issue is that a certain point, guests become "residents" in a legal sense, even if they are not on a lease. After that, they must be evicted to get them out, even though they are not paying rent and may be causing damages, or at least wear and tear.

The landlord of course also has a right to know who the tenants are :)

This is a serious matter for landlords. the specifics depend on your jurisdiction's judicial history, see nolo.com for an explanation of the legal principles.

Or go to their places instead :)