The Netherlands became the first European country to legalize gay-marriage in 2001, followed by Belgium two years later. In Spain, although there was opposition supported by the Catholic Church, same-sex marriage was legalized in 2005, with polls showing support from 62 percent of the population. Portugal followed suit in 2010.
Britain is currently introducing similar legislation. Bishops have written to newspapers to complain, but the country has seen no dissent approaching the French scale.
Opposition in France has united conservative, Catholic and far-right groups together with representatives of the country's Islamic community. The movement's unlikely figurehead is a comedien called Frigide Barjot, and who once entertained at a gay club called the Banana Cafe and recorded songs such as "Fais-moi l'amour avec two doigts" ("Make love to me with two fingers").
Barjot claimed to have brought a million to the streets for a demonstration in Paris back in January and is hoping for similar numbers this month. More legal challenges are planned even after the bill is signed into law.
Banners warning of the risks to French children posed by gay marriage and adoption rights have been strung along French highways, pamphlets carrying a similar message abound. Scuffles broke out among lawmakers during the parliamentary debate.
Barjot has denounced the more radical elements in the movement. Ultra-conservative groups have been blamed for death threats against politicians supporting the bill, vandalism of Socialist party offices and attacks on gays.
The fervor of opposition movement has been put down to the deep cleavages between left and right in France. Also stoking the fire are divisions between religious and secular traditions that date back to the Revolution of 1789, and that periodically flare up over issues ranging from schools' curricula to abortion.
Gay rights campaigner Ronzier points out that France has a history of street protests influencing politics, and that encourages demonstrators to believe they can change parliamentary opinion.
Others suggest the strength of the movement represents an attempt by French conservatives to find a rallying point following their defeat by President Francois Hollande and his Socialist Party in elections last year.
"The French people have an identity crisis," said Kevin, who works weekends selling gimp suits and whips at a store called Leather and Rubber, around the corner from the Rue des Archives.
"Some people aren't sure about their identity any more. Eith the Hollande government, the economic crisis - their lives don't have fixed anchor and that makes them resistant to change," he added.
Despite the current furor, French gays are confident the country will eventually be reconciled to marriage for all once the law is adopted.
"It will calm down, things will get back to normal and people will move on," Ronzier said.
In preparation, Paris hosted its first gay marriage salon on April 29, where would-be newly-weds could browse big day essentials offered by stylists, cake makers and florists.
The southern city of Montpellier, voted France's most gay-friendly city by the magazine Tetu, is hoping to hold France's first same-sex marriage in June. Paris is expected to follow soon after.
"I can't wait to marry all men and women of Paris who love each other," tweeted Anne Hidalgo, the Socialist favorite to win next year's mayoral election.
