A French Riviera chateau seized from late Russian oligarch Boris Berezovsky has been sold to an undisclosed buyer, according to France's agency for handling confiscated assets.
A local press report said the buyer was the Ukrainian-born co-founder of the WhatsApp messaging service.
Berezovsky, who died in the UK under inconclusive circumstances in 2013, fell out with President Vladimir Putin after helping him rise to power in Russia.
The powerful tycoon acquired the Chateau de la Garoupe on the Cote d'Azur in the 1990s while post-Soviet Russia's first president Boris Yeltsin was in power.
The mansion was then confiscated by French authorities in 2015, two years after Berezovsky was found hanged in exile at his home in England -- by then a bitter opponent of Putin.
A British coroner's inquest recorded an open verdict, meaning that there was not enough evidence to determine the exact cause of death.
France's Agency for the Management and Recovery of Seized and Confiscated Assets (Agrasc) did not disclose the identity of the buyer or the deal's price tag for confidentiality reasons.
But French regional daily Nice-Matin reported the property went to WhatsApp co-founder Jan Koum.
The newspaper said that the US billionaire, whose mega-yacht Moonrise was seen moored on the French Riviera all summer, paid nearly 65 million euros ($70 billion) for the property -- one of Agrasc's biggest sales since its foundation in 2010.
The property was built on the prestigious Cap d'Antibes by the British industrialist and MP Charles McLaren. Its rich history has seen it associated with the likes of Pablo Picasso, Cole Porter and Ernest Hemingway.
The chateau "represents exceptional architectural and cultural heritage," the Agrasc agency said.
The chateau, like the neighbouring property of the Clocher (Belltower) de la Garoupe, also owned by Berezovsky, was confiscated after being judged to be the proceeds of money laundering committed by investment company Sifi and its manager, Jean-Louis Bordes.
They were ruled to have acted as a front for Berezovsky.
In response to an initial complaint filed by Russia, French authorities needed 10 years to unravel the complex history of purchases including that of the Chateau de la Garoupe in 1996.
The Cote d'Azur has been popular with rich Russians dating back to visits from the imperial family at the turn of the century.
After the collapse of the USSR, it became a favourite playground for the country's oligarchs.
