Artur Widak/NurPhoto via Getty Images Facebook CEO Mark Zuckerberg in Dublin after an April 2 meeting with Irish politicians to discuss regulation of social media, transparency in political advertising and the safety of young people and vulnerable adults.

A new lawsuit accuses housing companies of using a discriminatory advertising tool on Facebook to block certain users from seeing their ads and using the social media giant to target younger Facebook users exclusively, according to a news release Wednesday by two law firms and a watchdog group.

The suit was filed on behalf of the nonprofit Housing Rights Initiative and District of Columbia resident Neuhtah Opiotennione, a 54-year-old who lawyers say was excluded from seeing advertisements for residences in her area. Lawyers say the housing companies used Facebook’s advertising algorithm to systematically weed out older prospective tenants.

Lawyers representing the Housing Rights Initiative and Opiotennione said Facebook allowed advertisers to set parameters on the age of users who would see their housing ads, thereby limiting the people who knew the residences were available to rent.

“If an advertisement is only sent to persons 22 to 55-years-old, no one older than 55-years-old will receive the ad,” they stated in the lawsuit.

The lawsuit finds seven companies ― whose combined ownership includes hundreds of apartment buildings ― legally culpable for housing discrimination. The companies cited in the lawsuit are Bozzuto, Greystar, Kettler, Wood Partners, Fairfield Residential, Fore Property and The Tower Companies.

In their filings Wednesday, lawyers include examples of allegedly discriminatory Facebook ads alongside screenshots of a feature that shows Facebook users why they are seeing certain ads on the social network.