The mask is incredibly rare (Picture: Getty)

An elderly couple are suing an art dealer after he allegedly withheld information about their mask before buying it at a knockdown price.

The unnamed couple in their eighties, from Nimes in France, were clearing out their home in 2021 when they decided to sell the ‘Ngil’ African mask.

They sold it to an art dealer, known as Mr Z, for £129 – but he went on to sell the mask just a few months later for £3.6 million at an auction in Montpellier, MailOnline reports.

The couple didn’t find out about the huge sale until they read about it in a newspaper- and they’re now suing Mr Z because they believe he cheated them and purposefully withheld his suspicions over the item’s value.

The item is sourced from the Fang people of Gabon, is used during weddings and funerals.

They’re a rare sight outside of the African country, with only a handful found in museums around the world.

Testing dated the mask to the 19th century and court documents describe the item as ‘exceptional in terms of its rarity’.

The couple came into possession of the mask because the husband’s grandfather was a colonial governor in Africa, according to industry media.

The lawsuit is ongoing, but the court of appeal in Nimes ruled the couple’s case ‘appears to be well-founded in principle’.

It’s been reported the proceeds of the sale have been frozen until the end of the case, and an offer from the dealer to pay the couple just under £260,000 was rejected.

The lawsuit is ongoing, but the court of appeal ruled the couple’s case ‘appears to be well-founded in principle’.