Felicien Kabuga was arrested after police tracked him down through his children.
Prosecutors on Wednesday filed a request for Felicien Kabuga to be transferred to United Nations custody for trial in international courts.
French intelligence agents spied on Kabuga's children in their effort to track him down.
The inquiry gathered pace in March after an intelligence-sharing meeting between investigators from France, Britain, and Belgium, where some of Kabuga's children live, as well as officials from the UN and Europe's Europol law enforcement agency.
"We realized ... that trail from the children protecting their father converged on Asnieres-sur-Seine," Eric Emeraux, head of the Gendarmerie's Central Office for Combating Crimes Against Humanity, told the Reuters news agency, referring to the Paris suburb where Kabuga was eventually arrested.
