France's top court has reversed a decision to extradite three Rwandans wanted by Rwanda for their alleged role in the 1994 Genocide against the Tutsi that claimed more than a million lives.

The Cour de Cassation overturned a November appeals court ruling approving the extradition of Claude Muhayimana and Innocent Musabyimana.

It also upheld a September decision by another court rejecting the extradition of Laurent Serubuga, a former colonel.

The Cour de Cassation said the men could not be judged for a crime that was not legally defined at the time the acts were committed.

Muhayimana, a French citizen since 2010, is accused of taking part in the massacre of Tutsis in Kibuye. Musabyimana was implicated in the Gisenyi murders.