CoStar Group has filed a lawsuit against a California-based firm for millions in damages, alleging the firm published CoStar’s apartment listings and photos without permission.

DC-based CoStar sued Apartment Hunters Inc and its co-owners, Kevin and Steven Shayan, on Dec. 18 in California, the Washington Business Journal reports. The suit alleges the company prominently displayed numerous CoStar listings and photos on its network of multiple websites, for which users pay a monthly access fee of $49.

The suit reads in part that Apartment Hunter’s model “is built upon systematically copying and appropriating without permission and then regurgitating other people's data.” CoStar’s allegations include the claim that Apartment Hunters cropped photos from Apartments.com to remove the CoStar logo before publishing the images to sites within its network.

CoStar is best known for compiling office rental rates and related data, but has made a big push into the area of multifamily listings. The company acquired Apartments.com in 2014 for $585M and added ApartmentFinder to its portfolio earlier this year for $170M. [WBJ]