The U.S. Department of Housing and Urban Development (HUD) is charging Facebook with violating the Fair Housing Act by "encouraging, enabling, and causing housing discrimination through the company’s advertising platform."

HUD alleges that Facebook unlawfully discriminates based on race, color, national origin, religion, familial status, sex, and disability by restricting who can view housing-related ads on Facebook’s platforms and across the internet. Further, HUD claims Facebook mines extensive data about its users and then uses those data to determine which of its users view housing-related ads based, in part, on these protected characteristics.

The Fair Housing Act prohibits discrimination in housing and in housing-related services, including online advertisements, based on race, color, national origin, religion, sex, disability, or familial status.

According to HUD’s Charge, Facebook enabled advertisers to exclude people whom Facebook classified as parents; non-American-born; non-Christian; interested in accessibility; interested in Hispanic culture; or a wide variety of other interests that closely align with the Fair Housing Act’s protected classes. HUD is also charging that Facebook enabled advertisers to exclude people based upon their neighborhood by drawing a red line around those neighborhoods on a map. Facebook also allegedly gave advertisers the option of showing ads only to men or only to women.

The Charge further asserts that Facebook also uses the protected characteristics of people to determine who will view ads regardless of whether an advertiser wants to reach a broad or narrow audience. HUD claims Facebook combines data it collects about user attributes and behavior with data it obtains about user behavior on other websites and in the non-digital world. Facebook then allegedly uses machine learning and other prediction techniques to classify and group users to project each user’s likely response to a given ad, and in doing so, may recreate groupings defined by their protected class. The Charge concludes that by grouping users who have similar attributes and behaviors (unrelated to housing) and presuming a shared interest or disinterest in housing-related advertisements, Facebook’s mechanisms function just like an advertiser who intentionally targets or excludes users based on their protected class.

Facebook said it was surprised by the decision and has been working with HUD to address its concerns and has taken significant steps to prevent ads discrimination across its platforms.