Facebook is reforming how it sells housing, employment and credit-related ads as part of a legal settlement with multiple civil rights advocacy groups over past discriminatory ad practices on the platform.

As part of the settlement, Facebook will pay $5 million and implement new protocols that are designed to prevent housing, employment and credit-related advertisers from targeting—or avoiding targeting—certain groups of people based on characteristics, including race, sex, religion and age. Facebook has limited the type of targeting advertisers can use when running housing, employment and credit ads, which are categories protected by federal law to prevent discrimination.

For instance, advertisers will no longer be able to target these types of ads using zip codes, and instead the advertisers can only target at minimum a 15-mile radius around the area of a housing or job opportunity.

"Our policies already prohibit advertisers from using our tools to discriminate," Facebook said in its announcement of the settlement on Tuesday. "We've removed thousands of categories from targeting related to protected classes such as race, ethnicity, sexual orientation, and religion. But we can do better."

Facebook says it will build an entirely new ad platform for advertisers to run housing, employment and credit campaigns.

Facebook also is building a portal where anyone can search and review all the housing ads currently running on the platform.

In 2016, a report from the nonprofit journalism group ProPublica raised the first questions about how advertisers could use sophisticated targeting tools on Facebook that violated the Fair Housing Act. It was possible to exclude targets with certain "ethnic affinities," people who were not technically identified as a certain race but who shared interests that aligned with certain races, like Native American, African American and Hispanic.

The report sparked concerns that housing, employment and credit advertisers could avoid showing opportunities to certain groups of people.

Since then, Facebook has implemented changes including eliminating ethnic affinities targeting for the sensitive advertising categories. It also created new warning that popped up in its ad platform requiring advertisers to certify that they would comply with anti-discriminatory ad laws.

In 2017, ProPublica and The New York Times jointly reported that employment ads could be targeted to discriminate against certain age groups, and last year there were reports of employers targeting jobs only to men. The changes eliminate sex and age targeting categories for housing, employment and credit ads, too.

The ad reforms were part of a settlement Facebook made regarding multiple cases that included complaints from National Fair Housing Alliance, Communication Workers of America and American Civil Liberties Union. Facebook says it will give those groups and other civil rights advocates continued access to test its systems for the potential for discrimination going forward.