Protesters Accuse Police of Improperly Using Barricades A federal lawsuit filed on Monday accused the New York Police Department of improperly using barricades to corral protesters and asked a judge to issue an order forbidding certain uses of barricades. The lawsuit stems from events that happened on Nov. 30, 2011, when President Obama attended a fund-raiser at the Sheraton Hotel in Midtown Manhattan. That night, the lawsuit said, about 100 people connected to the Occupy Wall Street movement showed up at the hotel to hold a demonstration. There, the lawsuit said, the group was directed by the police to stand between barricades arranged in a U shape near the southwest corner of 53rd Street and Seventh Avenue, about 100 feet away from the hotel. About 10 minutes after protesters entered the barricaded area, officers placed a final group of barricades into place, completely surrounding the protesters, the lawsuit said, adding that they were not permitted to leave the pen for about two hours. "Demonstrators were treated differently than others at the same intersection at the same time," the lawsuit states. "N.Y.P.D. officials told plaintiffs and others in the pen that they were being held "because" they were protesters. Tourists who were trapped in the pen as well as journalists were released while demonstrators were held. At the same time, the lawsuit asserted, traffic on Seventh Avenue was allowed to "flow freely." Five plaintiffs named in the lawsuit, which lawyers are asking be designated as a class action, said that the police violated their First, Fourth and 14th Amendment rights by holding them inside the barricaded area. Mark Taylor, one of the lawyers filing the suit, said that barricading the protesters also violated a provision of the police patrol guide that says people should be allowed to leave barricaded areas at any time, and which he said resulted from a ruling in a similar case in 2004. In that case, in which plaintiffs complained about the use of pens during a large antiwar demonstration, Judge Robert Sweet of Federal District Court in Manhattan, ruled that "the N.Y.P.D. is enjoined from unreasonably restricting access to and participation in demonstrations through the use of pens." Still, Mr. Taylor said, "The city has repeatedly violated the patrol guide." The lawsuit said that since the Occupy Wall Street protests began in September, the city had employed "a policy of using interlocking metal barricades to restriction access to and limit participation in protected First Amendment activity." The police have used metal barricades to surround Zuccotti Park, the park in Lower Manhattan that has been used as a base by protesters, and to block access to Wall Street from Broadway, the lawsuit said. The lawsuit also cited an episode in November in which the police used barricades to seal off the block on the Upper East Side where Mayor Michael R. Bloomberg lives and prevented people from gathering there to protest. A police spokesman did not immediately respond to a request for comment.