I may disagree with the previous responses. The violation is 42 USC 1983. Also, many states have a specific statute for violation of civil rights. (Of course, it would depend on the facts. If the police showed up and the landlord had a key and let them in, that is one thing. If they knew he was a landlord and not the possessor, that is another.)
The problem is damages. Hard as it is to believe, federally, our Constitutional rights have no inherent value. If a person, under color of authority, denies you of a right, your damages is how you were hurt. Feel bad's are not compensible. (Simplistic statement. Certainly there could be emotional damages that can be compensated for.)
Even in suing the landlord for trespassing, we have a similar result. You could get an injunction, but, the key to tort law is to put you back where you were. If you were not "hurt" (in money), it's tough to get anything but nominal damages.
Other than the exclusionary rule on evidence, the key is how you were hurt by the infringement. (If it was an infringement. From what you've said, I'd say yes. It's just I don't know all the facts.)