France has maintained its ban on gay marriage, with a constitutional court ruling that a lesbian couple with four children do not have the right to tie the knot.

The couple, a teacher and a paediatrician who have lived together for 15 years, had sought to bring France into line with EU neighbours like Spain, Belgium and Netherlands which allow same-sex couples to wed.

The ruling came as a TNS Sofres opinion poll said Friday that 58 percent of French people questioned were in favour of gay marriage, which is legal in ten countries around the world.

The court rejected the couple's argument that two articles in the French civil code which state that marriage can only be between a man and a woman were unconstitutional and discriminated against homosexuals.

But it said it was up to parliament to decide if the ban should be overturned, and not the constitutional authority.

The couple, Corinne Cestino and Sophie Hasslauer, currently enjoy tax benefits and other financial advantages because they are in the legally recognised civil partnership known here by its acronym PACS.

But they say they should be entitled to further benefits that marriage would bring.

"Marriage is the only solution in terms of protecting our children, sharing parental authority, settling inheritance problems and eventual custody if one of us were to die," they said before the ruling.

"It's scandalous," Ms Hasslauer said after the court decision, slamming a "minority attitude" in French society belonging to "a backward and outdated elite."

Gay rights activists also slammed Friday's decision.

"The constitutional court has missed an historic opportunity to put an end to discrimination that has become intolerable for more than three million gay and lesbians in France," said Caroline Mecary, a lawyer for gay rights groups.

She said gay activists were now hoping that next year's presidential and parliamentary elections would see the right-wing President Nicolas Sarkozy ousted and bring into power the Socialists, who are in favour of gay marriage.

- AFP