Some mayors of the Union for a Popular Movement right-wing party said they personally would refuse to perform same-sex marriages but also said others in their administrations would do the job and the law would be obeyed, Radio France Internationale reported.
"For me, marriage is a man and a woman and children. If a same-sex couple wants to get married, I'll ask for volunteers at City Hall and they'll do it. We will fulfill our public duties, even in Vienne," said Vienne's mayor, Jacques Remiller.
A couple could take criminal action against a mayor who refuses to marry them and could lead to a sentence of up to three years in prison, a fine of more than $58,000 and removal from office, the radio station reported.
The Socialist Montpellier Mayor Helene Mandroux performed the country's first gay marriage Wednesday, joining Vincent Autin, 40, and Bruno Boileau, 30, who have been a couple for five years, the radio station said.
Between 50 and 100 police officers were on hand surrounding City Hall and a mobile unit was on call to prevent protesters from disrupting the ceremony, the station said.