Q: I live in a rent-stabilized apartment in Chelsea, next door to an extremely noisy neighbor who treats the place like a one-person karaoke bar. Complaints to the landlord and police have never resolved the problem. I’m moving out soon, which will take care of the issue for me, but I feel terrible about a future tenant suffering through this person’s noise. If the landlord brings prospective tenants through the apartment, is it wrong for me to tell them about the problem? Is there any other resource that might let me put a warning out there?

A: You have a constitutional and statutory right to speak up about building conditions. However, you can’t go around bad-mouthing your neighbor to make it more difficult for your landlord to rent out the apartment. If you do, the landlord could sue you for intentionally persuading a tenant to not enter into a contract with the landlord.

“The safer thing to do would be to shut up,” said Samuel J. Himmelstein, a tenant lawyer and partner at the Manhattan firm Himmelstein, McConnell, Gribben, Donoghue and Joseph.

If the building had major ongoing problems, like a lack of heat or hot water, you could warn potential tenants. Tenants have done things like hang signs from windows stating the number of outstanding city violations, or hand out fliers to people entering the building. But even those steps carry some risk. “Proceed with caution, and only do it in an organized way,” with many tenants participating, Mr. Himmelstein said.