Massachusetts General Laws Part II. Real and Personal Property and Domestic Relations (Ch. 183-210) Ch. 186, § 15F

Any provision of a lease or other rental agreement relating to residential real property whereby the tenant agrees to waive his right to trial by jury in any subsequent litigation with the landlord, or agrees that no action or failure to act by the landlord shall be construed as a constructive eviction, shall be deemed to be against public policy and void.

If a tenant is removed from the premises or excluded therefrom by the landlord or his agent except pursuant to a valid court order, the tenant may recover possession or terminate the rental agreement and, in either case, recover three months' rent or three times the damages sustained by him, and the cost of suit, including reasonable attorney's fees.

Any agreement or understanding between a landlord and a tenant which purports to exempt the landlord from any liability imposed by this section shall be deemed to be against public policy and void.