Art advisors Simon and Michaela de Pury have had their $10 million (£7.9 million) commission affirmed by the Court of Appeals in London. The couple facilitated the sale of a Paul Gauguin artwork owned by Ruedi Staechelin on the strength of a handshake agreement.

“Once again, my role and the one of Michaela in this transaction, has been fully recognised and the integrity of a handshake deal in the art world has been upheld,” professed de Pury.

In 2015, de Pury acted as a broker for the $210 million (£165 million) sale of Gauguin’s Nafea Faa Ipoipo? (When Will You Marry?), on behalf of his childhood friend Staechelin. The striking painting was sold privately to the emir of Qatar, Sheikh Tamim bin Hamad al-Thani. Staechelin subsequently refused to pay the art advisors any fee for their involvement.

De Pury, alongside his former wife Michaela, won a court ruling in 2018 that granted them a $10 million commission (plus costs and interest) for the sale.

Last week Lord Justice Lewison rejected an appeal by Staechelin, a Swiss collector, to overturn last year’s ruling. Staechelin claimed that de Pury had failed to inform him of possible higher offers, voiding any agreement they may have had.

Despite the lack of written agreement, the court ruled that the commission was part of a “gentleman’s agreement”, which was sealed with a handshake.

Staechelin’s grandfather was an important collector of modern art and bought the oil painting for 18,000 Swiss francs in 1917. Nafea Faa Ipoipo? was painted by Gauguin in 1892 and depicts two Tahitian women in traditional Tahitian and Western-style clothing.

According to reports at the time of the sale, Nafea Faa Ipoipo? was supposedly the most expensive artwork ever sold at close to $300 million (£236 million). Yet during the trial in 2018, it was disclosed that it had actually been sold for $90 million (£71 million) less than originally reported.

De Pury, the former chairman of Sotheby’s Europe and board director at Gucci, stated “I am proud of my role in the sale of one of the world’s most expensive paintings ever sold for $210 million.”

The dispute has resulted in the collapse of a childhood friendship, whilst revealing the usually secretive dealings of the international art market.

“It is regrettable that for the first time in my long career in the art market, I was forced to take legal action against anyone, and in this case, a childhood friend… I look forward to continuing to put all my energy into my activities in the world of art and philanthropy,” assured de Pury.