A Paris court on Wednesday found a former Rwandan military policeman guilty of genocide and crimes against humanity during the 1994 slaughter in his home country and sentenced him to life in prison.
The court said it had found Philippe Hategekimana, 66, guilty of nearly all the charges against him.
He fled to France after the genocide, obtaining refugee status and then French nationality under the name Philippe Manier.
The trial of Hategekimana, which began last month, was the fifth such trial in France of an alleged participant in the massacres.
More than 800,000 people were killed between April and July 1994 according to UN figures, most of them from the Tutsi minority.
Plaintiffs accused Hategekimana of "using the powers and military force conferred to him through his rank in order to... take part in the genocide."
He denied the charges.
He was arrested in Yaounde, Cameroon's capital in March 2018 under an international warrant issued by French magistrates specialising in crimes against humanity.
France, one of the top destinations for fugitives from the massacres, has tried and convicted a former spy chief, two ex-mayors, a former hotel chauffeur and an ex-top official in similar trials since 2014.
But it has generally refused requests to extradite suspects to Rwanda, prompting President Paul Kagame to accuse Paris of denying Rwanda jurisdiction.