NEW ORLEANS — The New Orleans Police Department and the United States Department of Justice announced a far-reaching agreement on Tuesday to overhaul the city’s scandal-ridden police force and improve safety in a city that has had little of it.

“Effective policing and constitutional policing go hand in hand,” Attorney General Eric H. Holder Jr. said at an afternoon news conference with federal and local officials.

The 122-page agreement, known as a consent decree, states that “the ability of a police department to protect the community it serves is only as strong as the relationship it has with that community.” It calls for hundreds of new department policies governing the use of force, searches and seizures, arrests, interrogations, photographic lineups and more.

The agreement also deals with recruitment and training, performance evaluations and promotions, misconduct-complaint issues and even the lucrative off-duty work assignments that had become a potent source of corruption.