Tens of thousands of people marched in Paris Sunday in support of a government-sponsored bill that would legalize marriage and adoption for same-sex couples.

Demonstrators waved banners emblazoned with phrases such as "Equality of rights is not a threat" as they began marching Sunday from Denfert-Rochereau square in the southern part of the city.

The march drew 125,000 demonstrators into the streets, according to police. That was well above the number counted by police at a similar march in December, but far less than the estimated 340,000 that turned out for a demonstration by those opposed to the proposal two weeks ago.

About 63 percent of French people favor legalizing gay marriage, according to a survey released Saturday, up from 60 percent in December.

The French parliament is due to begin debate on the bill Tuesday and the bill is essentially guaranteed to pass the Socialist-dominated parliament. If it is approved, France would become the 12th country in the world to legalize same-sex marriage.

French civil unions, allowed since 1999, are at least as popular among heterosexuals as among gay and lesbian couples. But that law has no provisions for adoption or assisted reproduction, which are at the heart of the latest debate.

President Francois Hollande's Socialist Party has sidestepped the debate on assisted reproduction, promising to examine it in March after party members were split on including it in the latest proposal