The French Parliament approved legislation to allow same-sex marriage on April 23, 2013. See Scott Sayare, Amid Much Tumult, France Approves ‘Marriage for All’ (NY Times April 2013).
As expected, the legislation was challenged in the French Conseil Constitutionnel, but that challenge was rejected on May 17, and President François Hollande signed the legislation into law on May 18. The first marriages under the new law are expected by the end of May. See Steven Erlanger, Hollande Signs French Gay Marriage Law (NY Times May 18, 2013).
See also the post by Gilles Cuniberti, discussing the ruling of the Conseil Constitutionnel,on ConflictofLaws.net.