French mayors and their deputies cannot invoke their freedom of conscience to refuse to perform same-sex marriages that Paris legalized last May, the country's Constitutional Council ruled on Friday.
Seven mayors, backed by groups that led mass protests against gay nuptials early this year, asked France's highest constitutional authority for a ruling after the Interior Ministry threatened dissenters with jail or fines.
Gay marriage opponents condemned the decision and vowed to take the issue to the European Court of Human Rights.
"The legislator has not violated their freedom of conscience," the Council said in its ruling.
The government did not include an opt-out clause "to assure the law is applied by its agents and to guarantee the proper functioning and neutrality of public service," it added.
President Francois Hollande promised to legalize gay marriage as the major social reform of his five-year presidency. It is a touchstone issue for many of his Socialist supporters.
After the law came into effect, several mayors announced they would refuse to perform such marriages, prompting Interior Minister Manuel Valls to issue a memo warning they risked five years in jail or a 7,500-euro fine for discrimination.
Under French law, all couples must be married in civil ceremonies conducted by mayors or their deputies. Those choosing a religious wedding can only do so after this ceremony.
Ludovine de la Rochere, head of the "Demo for All" movement championing traditional marriage, rejected the ruling and said: "We will go to the European Court of Human Rights."
But Paris regional councilor Jean-Luc Romero hailed it as a setback for "homophobic mayors" and said: "This country's laws are not applied selectively."
Valls's memo reminded mayors and their deputies that they could empower a municipal councilor to perform a marriage if they were not available, but not out of opposition to the law.
According to the gay magazine Tetu, 510 same-sex couples married in Paris in the four months from June to September, accounting for 12 percent of all weddings celebrated during that period in the French capital.
Reporting By Emile Picy and Sophie Louet; Writing by Tom Heneghan; editing by Mark John
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