WASHINGTON — The Federal Trade Commission finished a settlement with Facebook on Friday over allegations that the company had violated its privacy policy, and in the process said it would re-examine its own practice of allowing companies to settle charges of wrongdoing while denying that they had done anything wrong.

The F.T.C.’s turnabout came in response to a blistering dissent from the Facebook settlement by one commissioner, J. Thomas Rosch, who said that allowing the company to deny charges it was agreeing to settle undermined the commission’s authority.

In November, the F.T.C. said that Facebook had deceived consumers by telling them that their personal information would be kept private, while “repeatedly allowing it to be shared and made public.”

The commission voted 3-1, with one abstention, to impose a 20-year consent order requiring Facebook to protect its users’ privacy. The company agreed to give consumers clear and prominent notice and to obtain their express consent before revealing information beyond their previously stated privacy settings, to maintain a comprehensive program to safeguard private information, and to obtain an independent privacy audit every two years.