Eric Holder, 45, has married his former stepmother, 48-year-old Elisabeth Lorentz, following a long-running court case that has ruled in their favour.
Unions between step parents and step children are banned by French law, but the prosecutors have decided not to appeal the decision by a local court to allow the marriage, the BBC has reported.
The French couple married in a village called Dabo in the north-east of the country, near the city of Metz. Dozens of people attended the ceremony, reportedly including Mr Holder’s father.
Lorentz said that her ex-husband had been supportive of them during their court case. According to French news site, Midi-Libre, the couple have been together for five years but have known each other for over 20 years. Lorentz was married to Mr Holder's father between 2003 and 2006. The couple are not blood relatives.
The couple had previously argued their case to the office of the President Francois Hollande but they received a letter back saying that such marriages are prohibited.