A carved mask from Central Africa, dating from the 19th century, was sold in France for 4.2 million euros ($4.6 million) on Saturday, despite Gabonese protesters in the auction house calling for the item's "'restitution".
The rare wooden "Ngil" mask, used in ceremonies by the Fang ethnic people of Gabon, smashed its estimate of 300,000-400,000 euros at the auction in the southern French city of Montpellier.
"It's a case of receiving stolen goods," a man describing himself as a member of the Gabonese community in Montpellier exclaimed from the back of the auction room, surrounded by half a dozen compatriots.
"We'll file a complaint. Our ancestors, my ancestors, from the Fang community, we will recover this object", the protester added, describing the mask as a "colonial ill-gotten gain".
Auctioneer Jean-Christophe Giuseppi said the auction was "entirely legal", as far as he was aware.
Accompanied by security guards, the demonstrators left the auction hall calmly, but continued their protest against the sale of African works of art.
Saturday's auction also included a Congolese chair which sold for 44,000 euros.
With added costs and fees, the total paid by the successful bidder for the Fang mask was 5.25 million euros, close to a record for such an item.
In 2006 a similar Fang mask brought in 5.9 million euros at a Paris auction.