PARIS -- Thousands of people marched in Paris on Sunday to show their support for a same-sex marriage bill that lawmakers will begin to debate on Tuesday.
Demonstrators waved banners emblazoned with phrases like "Equality of rights is not a threat" and chanted: "What do you want? Equality! When do you want it? Now!" Another placard showed a version of the French government's seal, but with two Mariannes kissing. Under the words "Liberty, Equality, Fraternity" was the slogan "No more, no less!"
According to the police, the march attracted about 125,000 people, twice the number that took part in a similar demonstration in mid-December. Two weeks ago, a rally by those opposed to the proposal drew what the police said were 340,000 people into the streets of Paris.
François Hollande, the Socialist president, promised during his campaign to legalize gay marriage within a year of taking office in May 2012. And with effective majorities in both houses of Parliament, Mr. Hollande and his government should be able to beat back various efforts by opponents to kill or amend the bill. It has been suggested that even given the long legislative process, the bill could become law as early as May.
In contrast to the opponents who demonstrated two weeks ago, many of the marchers on Sunday were relatively young and personally invested in the future of the law.
Nicolas Marquart, 37, a physiotherapist, made the trip from Strasbourg with his partner, with whom he is in a "civil solidarity pact," and another gay couple. "I'm here as a gay man, and because it would be nice, since we are still in the 21st century after all, to see our morals evolve. It would be a good thing to all have the same rights."
People are free to make their own choices, Mr. Marquart said, but for marriage, "everyone should have access to the choice."
Marion Bazin, 27, a saleswoman and law student from Paris, said she marched "to represent the rights of a whole segment of the population not necessarily recognized" -- not just gay men and lesbians, but "bisexuals, transsexuals and more, the whole group that does not fit the heterosexual bill." The civil solidarity pact, which provides limited protection, is not a marriage, she said. "It's simply a contract between two people -- marriage is bigger, it symbolizes much more."
It was upsetting, she said, to see so many people marching against same-sex marriage two weeks ago in the cold, "with children in strollers, explaining that marriage for homosexuals was unacceptable because we are not like other people and shouldn't have the same rights."
The draft law redefines marriage to stipulate that it is "contracted between two persons of different sex or of the same sex," and the words "father and "mother" in existing legislation are replaced by "parents." The bill also would allow married same-sex couples to adopt children.
The minister of justice, Christiane Taubira, told the Journal du Dimanche that the law, known as Marriage for All, "simply gives the same rights to and confers the same duties on homosexual couples: the conditions of marriage are unchanged."
But opponents, who include senior Roman Catholic, Jewish and Muslim leaders, say that by replacing father and mother with "parents," the law alters the natural order of procreation and will lead to moral confusion and the erosion of the centuries-old institution of marriage in the name of a small minority.
The government has chosen not to deal, for now, with the issue of government financing to help same-sex couples -- who say the number of children up for adoption is very small -- have children of their own.
The French, who are taught that every citizen has equal rights regardless of differences, generally support providing the same rights to gay and lesbian couples that are available to straight ones. According to the most recent poll by the French Institute of Public Opinion, which was released on Saturday, some 63 percent are in favor of same-sex marriage, and 49 percent favor the right of same-sex married couples to adopt.
Brian Ellner, an American advocate of same-sex marriage who helped lead the campaign for it in New York State, is here as an adviser to a lobbying group called All Out. He said the level of support in France was "quite amazing."
"France is always important as an exporter of ideas," Mr. Ellner said in an interview. "That's why it's important internationally. I believe a win in France would undoubtedly have an impact globally and even in the United States," where the Supreme Court is scheduled to hear arguments in March on two cases concerning same-sex marriage.
Frédéric Martel, an author and broadcaster who organized a gathering for government ministers, artists, intellectuals and other notables after the march, said: "We have to be in the streets and be strong. The bill will pass, we know it."
Mr. Martel said that Mr. Hollande, like President Obama, ducked the issue at first. "But Hollande finally decided you have to be on the side of modernity, not on the side of Iran and Saudi Arabia," he said.
Jack Lang, a prominent Socialist and a former French government minister who is gay, said: "It's a beautiful day, because it's a day that consecrates years of struggle to recognize these rights. Especially in the Socialist Party, at one time, it was not so obvious; we were not very numerous."
Some marched simply to show their solidarity with gay men and lesbians. Ida Papiernik, 72, a retired librarian, said she did not have strong feelings about same-sex marriage, "but what I do know is that I am absolutely against homophobia, so I am here to encourage these people."
The proportion of same-sex marriages in France would be small, she presumed, as would the number of adoptions by same-sex married couples. "I do not think civil marriage is in danger," she said. "I don't think we should make this a vital issue."
Arthur Touchot contributed reporting.
This article originally appeared in The New York Times.