France's top court on Tuesday upheld a 2018 decision by investigative magistrates to drop an investigation into the killing of Rwanda's former president Juvenal Habyarimana in 1994, which triggered a genocide.

The decision by the Cour de Cassation brings an end to the case which threatened Franco-Rwandan relations for more than twenty years.

Juvenal Habyarimana died in April 1994 after a plane that he and the then Burundi president Cyprien Ntaryamira were travelling in was downed near Kigali airport by rockets.

The incident triggered 100 days of violence in Rwanda, mainly by Hutus against minority Tutsis and moderate Hutus, in which some 800,000 people were slaughtered.

According to Reuters, the court in a written ruling cited the questions remaining on the identity of those responsible and inconsistencies in testimonies accusing members of the Tutsi-led Rwandan Patriotic Front of carrying out the attack.

France's opening of the judicial process against Rwandan officials and counter accusations by the post-genocide Rwandan administration that France was complicit in the massacres damaged relations between the two nations for years.

Ties however improved during President Emmanuel Macron's presidency.

In efforts to improve relations, Macron travelled to Kigali last year and acknowledged "the extent of our (France) responsibilities." He asked for forgiveness.

(With input from agencies)