Marie-Claude Bompard, the mayor of the southern French town Bollene, met with Amandine Gilles, 33, and Angelique Leroux, 27, on Friday to tell them she would not carry out their marriage because it was against her religious principles, Radio France Internationale reported.
Bompard is a member of the far-right Southern League, a split from Marine Le Pen's Front National.
Jean Vallier, Bollene council's head of communications, said the mayor's objection to the wedding was a "case of conscience." Vallier also accused the government of threatening Bompard with "disproportionate and illegitimate" sanctions for refusing to carry out the gay marriage law.
Meanwhile, Gilles and Leroux, who planned on getting married on Sept. 10, have written regional officials asking that Bompard be forced to carry out her legal obligations.