The measure would mean progress “not just for some people but for all society”, President François Hollande told the cabinet as it decided to start enacting one of his most publicised election campaign promises.
But he went on to declare debate on the matter “legitimate” and hoped that it would be “respectful of both religious beliefs and opinions”.
The bill, which will begin its passage through parliament in January, declared marriage to be “contracted between two people of different sex or of the same sex” and will extend the right to adopt a child to homosexual couples.
But gay rights groups are disappointed that it will not allow lesbian couples to medically assisted reproduction.
Outright opposition to the proposal has been led by the Catholic Church, whose declaration that it is against “human nature” is also backed by many Protestant, Muslim and Jewish clerics.
“A vision of the human being that does not recognise sexual differences would be a sham that would shake the foundations of our society,” declared French Catholic leader André Vingt-Trois at the annual meeting the country’s bishops.
On the far right, Front National MP Gilbert Collard has tabled a bill for a referendum proposing a constitutional ban on same-sex marriage.
Former Sarkozy prime minister François Fillon on Wednesday threatened to repeal the law if the right is returned to office. His rival for the UMP’s leadership, Jean-François Copé, has already said that he would not carry out same-sex marriages in his capacity of mayor of the city of Meaux.
But the right will be split on the question. UMP national secretary Frank Riester, one of the few members of his party to have come out as gay, openly supports the proposal, while others say they may back it or abstain, fearing that the party is lagging behind public opinion.
A recent opinion polls showed 65 per cent in favour of gay marriage, compared to 51 per cent in 1995, with 52 per cent in favour of adoption by gay couples.
Another poll in the south-western Languedoc-Roussillon region showed one in five mayors declaring that they would not carry out same-sex marriages.
The Socialist mayor of the northern town of Hantay, Désirée Duhem, has called off the marriage of two women planned for Saturday because “numerous violent and threatening reactions”.
In the US the states of Maine and Maryland endorsed same-sex marriage in referendums held at the same time as the presidential vote and Washington looked likely to do the same.
Spain’s constitutional court on Tuesday ruled that the country’s gay marriage law is consititutional.
The following countries have already legalised gay marriage:
- The Netherlands (2001);
- Belgium (2003);
- Spain and Canada (2005);
- South Africa (2006);
- Norway (2008);
- Sweden (2009);
- Argentina, Iceland, Portugal (2010);
- Denmark (2012).