Christie's is currently holding an auction for a remarkable collection of 700 jewelry items that belonged to Heidi Horten, an Austrian heiress.

Her late German husband established a retail empire during the 1930s, partly by acquiring department stores and other assets sold by Jews who were compelled to sell them as they fled Nazi Germany.

The auction house says the sale from "one of the greatest jewelry collections" is expected to reap some $150 million. Proceeds are to benefit her Vienna art museum, welfare for children, and medical research. Christie’s – as criticism of the auction grew – 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’s a record-setting ruby ring that Heidi Horten bought for $30 million in 2015.

A dazzling diamond necklace could fetch $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, "demanded" that Christie’s withdraw the sale, insisting that billions in riches that were amassed by Horten’s husband – Helmut Horten – were the "sum of profits from Nazi ‘Aryanization’ of Jewish department stores" under Nazi Germany."

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 "aryanized" – values were depressed by boycott measures, propaganda attacks, and other pressures from the authorities in the 1930s. Many Jews got no compensation; some received "hidden payments," while most buyers – possibly like Horten – "profited" from persecution measures.

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

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 "ideological" person, but neither did he resist Nazi laws, Hoeres said. Testimonies indicated Helmut Horten had "tried to help" some Jews, and he even "mocked" 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 – even getting arrested for a short time.

"We 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," Hoeres said in an interview. "You can’t say Horten was part of the resistance against the dictatorship."

Hoeres’ study said Horten’s personal fortunes swelled during the war years. It excerpted a document in English - attributed to the "Control Commission for Germany" under the postwar British authorities – which called Horten "a scoundrel of the worst type" and "a thoroughly depraved character" who should be brought to justice.

After the defeat of the Nazis in 1945, the British interned Horten 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 – riding in part on the brand name established during the Nazi period.

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

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

"We cannot erase history – but hopefully the money from this sale will go to do good in the future," Fawcett added.

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

The Christie’s catalog 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 – which features sapphires, emeralds, pearls, diamonds and much more – is the 90-carat "Briolette of India" diamond, the centerpiece of a necklace adorned with smaller diamonds, which has a pre-sale estimate of $10 million to $15 million.

The nearly 26-carat "Sunrise Ruby" also goes under the hammer: It fetched a record $30 million when Heidi Horten bought it at a Geneva auction eight years ago.

"Horten’s billions used to build this collection were also the sum of profits from Nazi ‘Aryanization’ of Jewish department stores," wrote Shimon Samuels, the Center’s director for international relations in a letter to Christie’s CEO Guillaume Cerutti.