A federal judge in New Orleans yesterday issued a restraining order that would prohibit the broadcast of a "60 Minutes" segment scheduled to air nationally tomorrow night, and lawyers for CBS News now are in New Orleans frantically trying to get the order lifted by an appeals court there.

The segment concerns racial tensions between the city's police and its black community--specifically, a case involving seven white New Orleans police detectives charged with beating, kicking and threatening blacks in connection with the fatal shooting in 1980 of New Orleans police patrolman Gregory Neupert. Four blacks were killed during the police investigation of that shooting.

U.S. District Judge Adrian Duplantier, who signed the restraining order, in January agreed to move the trial of the seven policemen from New Orleans to Dallas, and according to reports from New Orleans, the original restraining order was meant to black out the Dallas viewing area only from Sunday night's "60 Minutes" report. But the order was changed to a nationwide ban and the judge signed it.

Robert Chandler, vice president, director of public affairs for CBS News, said yesterday from New York that the restraining order was "clearly unconstitutional," constituted prior restraint, and is unprecedented in the history of "60 Minutes," which is the highest-rated news program in American television and each week places among the top 10 prime-time programs in national Nielsen ratings.

A three-judge federal panel in New Orleans has been notified of an emergency appeal and Chandler said he expects the judges to meet this morning and to lift the order. If the order is left standing, an alternate segment of "60 Minutes"--either a repeat or a report scheduled for a later broadcast--will be aired, Chandler said.

Duplantier, who could not be reached for comment, reportedly asked for a transcript of the "60 Minutes" report and, in line with CBS News policy, was denied it. He then issued the restraining order. Mike Wallace, the correspondent in the report, was traveling yesterday and could not be reached, a CBS News spokesman said.

In 1981, the Justice Department said it receives more complaints about police brutality from citizens of New Orleans than from any other city in the United States. Following the shooting of Neupert in the Algiers section of the city in 1980, police shot two men they said were suspects in the case and the girlfriend of one suspect. The police said all three were reaching for guns when shot.

The trial of the seven policemen, charged with violating civil rights during the investigation, is to begin Feb. 7 in Dallas.