Enlarge / The Facebook sign and logo at its Menlo Park, California, headquarters. (credit: Josh Edelson/Getty Images)

This article originally appeared on ProPublica on November 21, 2017. It has been lightly edited.

In February, Facebook said it would step up enforcement of its prohibition against discrimination in advertising for housing, employment, or credit.

But our tests showed a significant lapse in the company’s monitoring of the rental market.