The city “promotes a culture of rampant brutality, especially against people of color,” the lawsuit said, adding that the police are 14 times more likely to use force against black men between the ages of 20 and 34 than against their white counterparts.

The most recent crisis was spurred by the release, a year and a half ago, of a video showing a white officer shooting a black teenager 16 times.

The video contradicted the police accounts of the death, which claimed the teenager had been moving menacingly toward them with a knife.

A mayoral task force formed in the aftermath of that scandal later reported that the city’s own data “gives validity to the widely held belief the police have no regard for the sanctity of life when it comes to people of color.”

But the prospect of a consent decree faded after the election of President Trump, which led to the appointment of Attorney General Jeff Sessions, who has long criticized such arrangements, even calling them “dangerous” because they circumvent the will of voters.

Since he took office, Mr. Sessions has also ordered a sweeping review of federal police interventions, declaring that “the individual misdeeds of bad actors should not impugn” the work police officers perform “in keeping American communities safe.”

But private plaintiffs can also seek a court-enforced settlement. The new lawsuit essentially seeks to persuade a federal judge to order changes similar to what might have occurred under a federal consent decree with the Justice Department.