GENEVA -- Christie鈥檚 is auctioning a staggering 700 pieces of jewelry from the , an Austrian heiress whose German husband built a retail empire starting in the 1930s 鈥 in part from department stores and other assets sold by desperate Jews as they fled Nazi Germany.

The auction house says the sale from 鈥渙ne of the greatest jewelry collections鈥 is expected to reap some US$150 million. Proceeds are to benefit her Vienna art museum, welfare for children, and medical research. Christie鈥檚 鈥 as criticism of the auction grew 鈥 said it planned to chip in some of its profits from the sale to Holocaust education.

The sale has already begun online, but also takes place in-person in two parts on Wednesday and Friday at a ritzy Geneva hotel. There鈥檚 a record-setting ruby ring that Heidi Horten bought for US$30 million in 2015. A dazzling diamond necklace could fetch US$15 million or more. And the auction house says the sale features more Bulgari jewels than ever assembled for a single auction.

But the auction has been steeped in controversy: The Simon Wiesenthal Center, a Los Angeles-based Jewish human rights group, 鈥渄emanded鈥 that Christie鈥檚 withdraw the sale, insisting that billions in riches that were amassed by Horten鈥檚 husband 鈥 Helmut Horten 鈥 were the 鈥渟um of profits from Nazi 鈥楢ryanization鈥 of Jewish department stores鈥 under Nazi Germany.鈥

Helmut Horten's story was complicated, said Peter Hoeres, a historian at the University of Würzburg, in Germany. He was commissioned by Heidi Horten to write an extensive study looking into her husband's business empire.

The report lays out the creeping, and eventually overbearing, squeeze put on Jewish-owned businesses. Tens of thousands of Jewish-owned retail stores were 鈥渁ryanized鈥 鈥 values were depressed by boycott measures, propaganda attacks, and other pressures from the authorities in the 1930s. Many Jews got no compensation; some received 鈥渉idden payments,鈥 while most buyers 鈥 possibly like Horten 鈥 鈥減rofited鈥 from persecution measures.

Earlier this month, the Simon Wiesenthal Center called for the withdrawal of the auction 鈥 which has now already begun online 鈥 saying Horten helped build his business empire by buying 鈥渁t a cut price鈥 the department store where he worked as Adolf Hitler came to power in 1933 from its Jewish owners, Strauss and Lauter, 鈥渨ho fled to the U.S.鈥

Starting in 1933, the Strauss and Lauter families, owners of the Alsberg department store in Duisburg, suffered from boycott calls, and other harassment, according to the report. Their customers were also subjected to intimidation.

Horten was not an 鈥渋deological鈥 person, but neither did he resist Nazi laws, Hoeres said. Testimonies indicated Helmut Horten had 鈥渢ried to help鈥 some Jews, and he even 鈥渕ocked鈥 Nazi leaders at times, but he also fired some Jewish employees to abide by Nazi race laws. He joined the Nazi party in 1937, and was expelled seven years later 鈥 even getting arrested for a short time.

鈥淲e were in 27 archives in Europe, and we read thousands of pages of sources, and I think we in the end (discovered) ... there is not a saint and not a devil, but there is Horten who ... benefited from the circumstances of the tyranny of the Nazis,鈥 Hoeres said in an interview. 鈥淵ou can鈥檛 say Horten was part of the resistance against the dictatorship.鈥

Hoeres鈥 study said Horten鈥檚 personal fortunes swelled during the war years. It excerpted a document in English 鈥 attributed to the 鈥淐ontrol Commission for Germany鈥 under the postwar British authorities 鈥 which called Horten 鈥渁 scoundrel of the worst type鈥 and 鈥渁 thoroughly depraved character鈥 who should be brought to justice.

After the defeat of the Nazis in 1945, Horten was interned by the British for two years and lost a lot of his holdings. But in 1948, after being released, he leveraged loans to create what would become the fourth-largest department store chain in Germany 鈥 riding in part on the brand name established during the Nazi period.

The businessman amassed a far greater fortune than he had built before or during the war, said Hoeres, who has no connection to Christie鈥檚.

鈥淢r. Horten鈥檚 business activities during the Second World War are well-documented, and that is something that Christie鈥檚 carefully considered when pitching for this collection,鈥 said Max Fawcett, head of the jewelry department at Christie鈥檚 Geneva. 鈥淲e took on this collection in the understanding that 100% of the final sale proceeds will go to philanthropic causes.鈥

鈥淲e cannot erase history -- but hopefully the money from this sale will go to do good in the future,鈥 Fawcett added.

The jewelry was not purchased from Jews, but the riches that paid for it had their roots in the Nazi era. Christie鈥檚 said the jewelry was all bought starting in the early 1970s 鈥 more than a quarter-century after the end of the war 鈥 up through last year, when Heidi Horten died. Her husband died in 1987. Christie鈥檚 noted that he had 鈥減urchased Jewish businesses sold under duress.鈥

The Christie鈥檚 catalogue for the auction focuses entirely on Mrs. Horten: in one photo, she is shown smiling as she holds a baby chimpanzee in her arms. Initially, it made no reference to her husband or the origins of his wealth.

Among standout pieces in the auction 鈥- which features sapphires, emeralds, pearls, diamonds and much more 鈥 is the 90-carat 鈥淏riolette of India鈥 diamond, the centrepiece of a necklace adorned with smaller diamonds, which has a pre-sale estimate of US$10 million to US$15 million. The nearly 26-carat 鈥淪unrise Ruby鈥 also goes under the hammer: It fetched a record US$30 million when Heidi Horten bought it at a Geneva auction eight years ago.

鈥淗orten鈥檚 billions used to build this collection were also the sum of profits from Nazi 鈥楢ryanization鈥 of Jewish department stores,鈥 wrote Shimon Samuels, the Center鈥檚 director for international relations in a letter to Christie鈥檚 CEO Guillaume Cerutti.