A street preacher sued Thursday to block a city ordinance that restricts religious or political speech on Bourbon Street after dark.

In his federal lawsuit, New Orleans pastor Paul Gros claimed the city's "aggressive solicitation" ordinance sets unconstitutional limits on free speech.

Gros said he was preaching on Bourbon Street with his wife, another pastor and a friend on the night of May 15 when police ordered him to stop.

"They told him if he didn't stop he would be arrested," said one of his attorneys, Nate Kellum.

Gros left without being arrested. Less than a month ago, however, police arrested several preachers on Bourbon Street during the Southern Decadence gay pride festival.

The city council adopted the ordinance in October 2011. A violation is a misdemeanor punishable by up to six months in jail and a $500 fine.

The measure makes it a crime for anyone to "loiter or congregate on Bourbon Street for the purpose of disseminating any social, political or religious message between the hours of sunset and sunrise."

Mayor Mitch Landrieu, Police Superintendent Ronal Serpas and the city council's members are named as defendants in the lawsuit.

Landrieu's office and City Councilmember Kristin Gisleson Palmer, who sponsored the ordinance, didn't immediately respond to requests for comment.

Palmer has said it was crafted as a public safety measure to help with crowd control.

Kellum said he wasn't aware of any similar ordinances in other cities.

"I've never seen anything like it, really," Kellum said.

The lawsuit said Gros was a "professing Christian" and pastor of Vieux Carre Assembly of God Church in the French Quarter, a block from Bourbon Street. Gros has been preaching on the French Quarter's streets for 30 years and doesn't intend to harass anyone or solicit any funds, his suit said.

"Because Pastor Gros firmly believes a large number of people found on Bourbon Street at night desperately need to have saving faith in Jesus Christ, he wants to go there at that time and share the gospel message with them," the suit said.

Attorneys for the Center for Religious Expression in Memphis, Tennessee, and the Alliance Defending Freedom in Scottsdale, Arizona, filed the suit on behalf of Gros.