Facebook has failed to eliminate discriminatory housing ads from its platform despite promises to do so, a lawsuit filed Tuesday by the National Fair Housing Alliance says.

The organization filed a lawsuit against Facebook in the U.S. District Court for the Southern District of New York in conjunction with the Fair Housing Justice Center in New York, the Housing Opportunities Project for Excellence in Miami and the Fair Housing Council of Greater San Antonio. The lawsuit alleges that steps Facebook has taken to eliminate illegal advertising practices have not been enough and advertisers can still use the platform to discriminate in protected categories like housing.

The organizations note in their complaint that their lawsuit hits Facebook in the same year as the 50th anniversary of the Fair Housing Act, the law that makes exclusionary advertising in housing illegal. Violators of the act can face fines and punitive damages in federal court.

“Facebook enables a real estate company or landlord to discriminate by selectively targeting housing advertisements to exclude specific populations. Facebook’s platform is the virtual equivalent of posting a for-rent sign that says No Families with Young Kids or No Women, but it does so in an insidious and stealth manner so that people have no clue they have been excluded on the basis of family status or sex,” Fair Housing Justice Center Executive Director Fred Freiberg said in a statement.

Facebook first came under fire for allowing potentially illegal ads on its platform in 2016, when ProPublica published a report showing that Facebook allowed advertisers to target or exclude users by “ethnic affinity.” Facebook said it put in place measures to remove that ability, but last November ProPublica again found that advertisers could still exclude users by race. Facebook temporarily blocked advertisers from excluding any users from seeing their ads in response. The National Fair Housing Alliance created its own advertisements in response to those events.

The plaintiffs in the case created an ad campaign and found that they were able to exclude women and families with children, as well as people whose Facebook profiles expressed interest in areas related to other protected characteristics: disabled veterans, disabled parking permits, English as a second language and the Spanish-language media platform Telemundo.

Under the names of fake real estate companies, the fair housing groups posted ads for rental housing that excluded categories like “stay-at-home moms” and “corporate moms” in Washington, D.C., New York, Miami and San Antonio. Facebook approved every ad the organizations created within one hour, the complaint said. The organizations removed the ads themselves.

Facebook denied the claims in the lawsuit.

“There is absolutely no place for discrimination on Facebook. We believe this lawsuit is without merit, and we will defend ourselves vigorously,” a Facebook spokesperson said.

This lawsuit hits Facebook as the company is grappling with a global crisis over user data. Data from 50 million users ended up in the hands of Cambridge Analytica, a group working to support Donald Trump’s presidential campaign.

“Facebook’s use and abuse of user data for discriminatory purposes needs to stop,” National Fair Housing Alliance CEO Lisa Rice said in a statement. “It is already a challenge for women, families with children, people with disabilities and other under-served groups to find housing. Facebook’s platform that excludes these consumers from ever seeing certain ads to rent or buy housing must be changed immediately. Facebook ought to be opening doors to housing opportunities instead of closing them.”

Email Emma Hinchliffe