Félicien Kabuga, one of the most wanted suspects in the Rwandan genocide, has been arrested near Paris, the French justice ministry has announced.
Mr Kabuga was detained by gendarmes in Asnières-sur-Seine, where he had been living under a false identity.
The International Criminal Tribunal for Rwanda has charged the 84-year-old with genocide and crimes against humanity.
He is alleged to have been the main financier of the ethnic Hutu extremists who slaughtered 800,000 people in 1994.
They were targeting members of the minority Tutsi community, as well as their political opponents.
The United States had offered a $5m (£4.1m) reward for information leading to Mr Kabuga's arrest.
Who is Félicien Kabuga?
By Will Ross, Africa editor, BBC World Service
The businessman from the Hutu ethnic group is accused of being one of the main financiers of the Rwandan genocide, paying for the militias that carried out the massacres.
He also founded and funded the notorious Radio Télévision Libre des Mille Collines (RTLM), a Rwandan broadcaster that actively encouraged people to search out and kill anyone who was from the Tutsi ethnic group.
The fact that he has been found on the outskirts of Paris living under a false name is surprising.
For many years, Félicien Kabuga was thought to be living in Kenya, where powerful politicians were accused of thwarting efforts to get him arrested.
More than a quarter of a century after the genocide, he will go on trial at an international court.
