French President Francois Hollande on Thursday denounced the violence which took place on Wednesday night during a rally to protest passage of a law legalizing marriage and adoption for gay and lesbian couples.

“Homophobic acts, violent acts have been committed,” Hollande said in a statement. “The right to protest is recognized by our constitution and accepted by the French. But no protest must degenerate.”

On Wednesday, the National Assembly began its final debate on the bill. The measure has cleared both houses of parliament, but minor alterations in the Senate sent the bill back to the National Assembly.

Interior Minister Manuel Valls also condemned the violence. He said protesters damaged cars and public property along Paris' famed Champs-Elysees avenue and attacked police officers and journalists. According to police, 11 people were detained.

Police estimated the crowd at 2,400. Organizers disagreed, putting the figure at 8,000.

Another 24 people who participated in a counter-protest denouncing the anti-gay rhetoric were arrested, police said.

Violence also broke out at a gay bar in the northern city of Lille. Police arrested four men after they verbally and physically attacked the owner of Vice & Versa. The owner said his partner and a server were also injured and that the attack was related to the debate.

The lower house is expected to give final approval to the bill on Tuesday.

Opponents are planning a mass protest in Paris on May 26.