French Open organisers defended their security arrangements after anti-gay marriage protesters, one letting off a flare and running on court, briefly interrupted the final between Spaniards Rafa Nadal and David Ferrer on Sunday.
A police source told Reuters that seven people had been formally detained on Sunday night after the showpiece match was disrupted and protests broke out elsewhere at Roland Garros in Paris. Five others were released after initial questioning.
A group called "Hommen" claimed responsibility for the protests on social-networking sites Facebook and Tumblr, describing themselves as "standard-bearers of the resistance against gay marriage".
French president Francois Hollande last month signed into law a bill allowing same-sex marriage amid a series of large, and sometimes violent demonstrations.
Security guards were called into action during the final when two bare-chested men stood up in one of the front rows behind the players' benches on court Philippe Chatrier at the end of the sixth game of the second set.
One protester, wearing a white face mask, let off a flare and ran onto the court towards Nadal.
He was brought down by a member of security staff before being dragged out with his accomplice, who did not get the chance to step onto the court.
Earlier four other protesters were evicted from the stadium by security while six were removed from the neighbouring Court Suzanne Lenglen where Legends matches were taking place. They were holding banners marked "Hollande Resign!" and accusing the government of trampling on the rights of children.
"Twelve people have tried to disrupt the match. They have been caught by the security staff of the tournament and been handed over to the police," a police source, who declined to be named, said.
"They are being questioned by the police."
Tournament director Gilbert Ysern told reporters: "This kind of thing is regrettable but it has been taken care of remarkably by our security staff.
"I apologised to the two players. At the time, you are scared but we were quickly reassured.
"These people are good-for-nothings."
Nadal's coach and uncle, Toni Nadal, told reporters he was not scared but runner-up Ferrer joked that his opponent had been affected.
"It's funny, Rafa was scared a little bit," a smiling Ferrer said.
"It's strange but I did not lose my focus."
The first same-sex marriage was celebrated in Montpellier on May 29.
This is not the first time the French Open final has been interrupted by a court invader. Four years ago, a fan tried to put a hat on Roger Federer's head during his victory over Sweden's Robin Soderling.