Fragile relations between France and Rwanda have plunged after Paris reopened a controversial investigation into the 1994 assassination of the Rwandan president Juvenal Habyarimana.

Opened in March 1998, the investigation focused on the shooting down of the plane on 6 April 1994, killing both Habyarimana and the President of Burundi Cyprien Ntaryamira, as well as their entourages and a French air crew. The killing triggered the country's 1994 genocide in which ethnic Hutu extremists killed more than 800,000 Tutsis and moderate Hutus.

France and Rwanda's difficult relations

France was Rwanda's main European backer until the genocide.

Rwanda cut all ties with France following the Rwandan war, after it accused France of complicity with the genocidaires – including training and arming the Hutu militias who were the main force behind the slaughter. Paris has continuously denied the charge.

In 2006, controversial former French judge Jean-Louis Bruguière called for senior Rwandan military officers, including Kagame, to be put on trial for the attack after he accused Kagame and his allies of shooting down's plane. Kagame dismissed the allegations as "ridiculous" and severed ties once again.

The investigation already led to a breakdown of diplomatic relations between the two countries in 2006 and 2009 resulting in it being closed twice because investigators failed to reach any conclusions. It was reopened on 7 October after a French judge accepted to hear a former general who claims President Paul Kagame was involved.

In a speech in the Rwandan capital Kigali on 10 October, Kagame raised the possibility of a new rift in diplomatic relations between the two countries.

"The judicial system of Rwanda is not subordinate to France or France's interests," Kagame told officials at an official judicial function, according to Reuters. "It should be France in the dock being tried, not anybody in Rwanda and not Rwandans."

Kagame added: "If starting all over again is a showdown we will have a showdown, there is no problem about that."

A controversial investigation

Rwanda's former chief of army staff Faustin Kayumba Nyamwasa, now in exile in South Africa after he survived an attempt to murder him, claims Kagame was linked to attack.

Kagame alleges that Habyarimana's own supporters shot down the plane because they disapproved of a peace deal the then president had negotiated with Kagame's rebels, the Rwandan Patriotic Front (RPF). French judges have previously called for senior Rwandan military officers, including Kagame, to be put on trial for shooting down the plane.

The French judge in charge of the investigation accepted to hear Nyamwasa, who had requested to be heard by investigators, according to a French judicial source.

Rwanda genocide
27 June 1994: French soldiers pass Hutu troops from the Rwandan government forces near Gisenye, about 10km from the border with Zaire. The French military was later accused of ferrying extremist Hutu militiamen to a mountain hideout in Rwanda to slaughter thousands of ethnic Tutsis Pascal Guyot/AFP