Some Jewish groups have called on Christie's to stop the sale, but the auction house says the proceeds are going towards "charities" and "Holocaust research and education".
Christie's auction house in Geneva is selling hundreds of jewels that belonged to Austrian billionaire Heidi Horten, whose German businessman husband made his fortune under the Nazis.
The auction house will offer 700 lots from Horten’s collection, including "unique and exceptional pieces" from 20th-century designers including Cartier, Harry Winston, Bulgari and Van Cleef & Arpels.
The whole collection has an estimated value of more than $150 million (€137 million).
The sale could eclipse previous records set by Christie's in sales of properties that belonged to actress Elizabeth Taylor in 2011 and the "Maharajas and Mughal Magnificence" collection in 2019, both of which exceeded $100 million (€91 million).
Leading the collection is a rare Cartier ruby and diamond ring, which weighs in at 25.59 carats and has "a saturated pigeon-blood red colour and fine purity", according to the auction house.
"What makes this collection particularly remarkable is the breadth and quality of the gemstones," said Max Fawcett, head of jewellery at Christie’s in Geneva.
"You’ll find everything from costume jewellery and one-of-a-kind haute joaillerie pieces, to historic jewels with exceptional provenance," he added.
Heidi Horten died last year aged 81. According to Forbes, she was worth $2.9 billion (€2.65 billion).
Nazi party membership
According to a report published in January 2022 by historians commissioned by the Horten Foundation, her husband Helmut Horten was a member of the Nazi party before being expelled.
In 1936, three years after Adolf Hitler came to power in Germany, Horten took over the textile company Alsberg based in the western city of Duisburg after its Jewish owners fled.
He later took over several other shops that had belonged to Jewish owners before the war.
"How did a 27-year-old take over a major department store? Did he put the (Jewish) seller under pressure?" the historians wrote.
"The giant among the West German entrepreneurs remained silent about his activities in the years 1933-45. And so the image of an unscrupulous profiteer endures today."
The Allied denazification committee exonerated Helmut Horten after the war. He died in Switzerland in 1987.
On its website, Christie's says that "the business practices of Mr Horten during the Nazi era, when he purchased Jewish businesses sold under duress, are well documented".
Christie’s CEO, Guillaume Ceruttitold said the auction house's decision to take on the sale was made after "careful consideration".
"It was never Christie's intention to hide information about the well-documented history of Mr Horten and we have added relevant information to our sale materials and website to ensure that the facts are clear to all."
Proceeds to go to charities
The auction house has stressed that the proceeds from the sale will go to the Heidi Horten Foundation, established in 2021 to support the eponymous art collection, as well as to medical research, child welfare and other philanthropic activities that the wealthy heiress supported.
"For our part, Christie’s will make a significant contribution from its final proceeds of the auction to an organisation that further advances Holocaust research and education," it added in its online statement.
400 of the Horten lots will be sold at Christie's Geneva auction house from May 10 to 12.
Other pieces will be sold online until May 15 and in November.