French police arrested Rwandan genocide suspect Felicien Kabuga on Saturday.
The 84-year-old had been pursued by international justice for 25 years over crimes allegedly committed during the 1994 genocide.
The French Justice Ministry said gendarmes arrested him at 0530 GMT on Saturday. He had been living under an assumed name in a flat in Asnieres-Sur-Seine, near Paris.
He is believed to have held the purse-strings of Rwanda's so-called hate media, which incited ethnic Hutus to murder Tutsis.
His son-in-law was arrested in Germany in 2007.
A top United Nations prosecutor welcomed the arrest.
"The arrest of Felicien Kabuga today is a reminder that those responsible for genocide can be brought to account, even 26 years after their crimes," said Serge Brammertz, chief prosecutor of the Mechanism for International Criminal Tribunals in The Hague.
Kabuga is Rwanda’s most-wanted man and is the subject of a $5 million (€4.6 million) bounty offered by the United States.