A poll published Tuesday revealed nearly two-thirds of the French support gay marriage, as Catholic bishops urged their followers to pray for the maintenance of traditional family standards.
The Ifop poll, due to be published on Wednesday by digital magazine La Lettre de l'Opinion, found 65 percent of the French support gay marriage with a smaller majority (53 percent) in favour of gay couples having the right to adopt children.
Both marriage and adoption will become possible for gay and lesbian couples under legislation which the Socialist government in France has pledged to enact before the end of 2013.
The move is being resisted by the Catholic Church and bishops have made their campaign an implicit theme of services to mark the Assumption holiday on Wednesday.
A prayer to be read out at services in every parish of France will include a passage expressing the wish that children and young people "cease to be the objects of the desires and conflicts of adults in order to fully benefit from the love of a father and mother."