Employee-rights lawyers are pressing a lawsuit against Facebook Inc. that alleges the social media company's advertising platform unlawfully permits businesses to promote job, credit and housing opportunities to white, wealthy users and exclude people of color or those in less affluent zip codes.

The class action in San Jose, California, federal district court claims Facebook's advertising tool that allows businesses to exclude groups, such as African-Americans, Latinos and Asian-Americans, from advertising opportunities violates federal housing and civil rights laws.

The plaintiffs firms involved in the case—including Outten & Golden, which last year hired P. David Lopez, the former general counsel to the Equal Employment Opportunity Commission—on May 18 asked a judge to reject Facebook's push to end the litigation. Facebook's lawyers at Munger, Tolles & Olson contend the company is shielded from liability under a federal law that gives wide protection to companies that publish third-party content. The lawyers also argue Facebook forbids advertisers from violating anti-discrimination laws.