We just got hold of a lawsuit filed against Rihanna today.

Christian Moeller is suing over some property, claiming Rihanna has been trampling all over his property.

Moeller is a professor of design and media art at UCLA. Moeller has created spaces for the W Hotel in Hollywood.

Here's what happened. Rihanna rents a home owned by Stephen Yacobian, whose house is next door to Moeller's. Moeller gave Yacobian an easement -- the right to drive cars on a portion of Moeller's property.

But two years ago, Yacobian renovated the property and the easement wasn't really being used. To make matters a lot worse, since Rihanna moved in she's been allowing cars to drive on Moeller's lawn to get to her driveway... and the suit claims sometimes the cars just sit there on the lawn.

So Moeller wants the easement eliminated. As for Rihanna, Moeller is suing her for allowing people and cars to trespass on his property.