Tens of thousands of people registered a final, furious protest against same-sex marriage on Sunday, days before the first wedding ceremony under a new law.
At least 150,000 protesters converged on Paris, marshalled by more than 4,500 police who were deployed after the government warned of a risk of violence and disruption.
Riot police evicted about a dozen far-right activists who used ladders to climb on to the roof of the Socialist party headquarters and unfurled a banner saying “Hollande resign”.
The night before the demonstration, 50 people were arrested after chaining themselves to metal barriers they had placed in the middle of the Champs Elysées and firing smoke canisters. A van carrying masks, banners and smoke bombs was seized by police.
The new law – the key social reform of the Socialist president, François Hollande – was officially adopted last week, making France the 14th country in the world to legalise same-sex marriage. The first wedding will take place between two gay activists in Montpellier on Wednesday.
But the reform has sparked months of bitter political debate and the biggest rightwing street demonstrations in decades, including hundreds of arrests after clashes between police and demonstrators in the runup to the parliamentary vote. Rights groups have recorded a sharp increase in homophobic acts across France.
Protesters from the anti-same-sex marriage movement converged in their thousands at the Invalides in Paris, while a more hardline demonstration led by Catholic traditionalists gathered near the Opera. Nationalist youth groups attended the latter demonstration, with one calling for a “national revolution”.
Among the crowds, one demonstrator led a donkey carrying a placard: “I’m an ass, I voted Hollande.”
Divisions over the law continue to cause tensions on the French right, with the government warning of a resurgence in far-right groups and a small number of “ultras” on the fringes.
The most radical protesters have grouped together under the banner “Printemps Français” (French spring), a loose grouping of traditionalists and far-right associations, which the French interior ministry last week threatened to outlaw.
Tensions were exacerbated by the suicide last Tuesday of a far-right essayist, Dominique Venner, who shot himself at the altar of Notre Dame cathedral on Tuesday after leaving a blogpost railing against immigration and the “vile” law legalising same-sex marriage.
The comedian Virginie Tellene, known by her stage name Frigide Barjot, who has led the anti-gay marriage movement and been its figurehead, did not attend the demonstration in order to defend what she called “peace and freedom of expression”. She is under police protection having complained of death threats and pressure from the extreme rightwing.
Jean-François Copé, leader of the rightwing UMP party, keen to capitalise on the protest movement in the runup to next year’s local elections, attended the demonstration in Paris after other key figures in his party, including the former foreign minister Alain Juppe, had cautioned against it.
The prime minister, Jean-Marc Ayrault, attacked UMP politicians for supporting the demonstration, warning that they were taking “a heavy responsibility” in “sparking tension and radicalisation”.
Christian Jacob, head of the UMP group in parliament, who was at the rally, said: “Even though the law has been voted in, it doesn’t mean we can’t contest it.”
Watch video of the march, courtesy of Al Jazeera America, below.