Klaus Perls with Calder in his Saché studio, circa 1971. Courtesy Calder Foundation.

A lawsuit by the estate of artist Alexander Calder against his longtime dealer Klaus G. Perls includes allegations of secret Swiss bank accounts, tens of millions of dollars' worth of works unaccounted for, and sales of dozens of forgeries. Filed in New York State Supreme Court, the complaint accuses Perls of fraud, according to a story in the New York Times.

Perls represented Calder from 1954 until the artist's passing in 1976, and the complaint accuses him of depriving Calder's estate of tens of millions of dollars in revenue from works the dealer allegedly secreted away.

In court papers, Perls's lawyer, Steven W. Wolfe, has asserted that the accusations result "from only the sort of gaps in records that are normal when tracking 25-year-old transactions from a gallery that has been closed for more than 15 years," the story adds. Perls died in 2008.

The Calder Foundation maintains in court papers that nearly 700 sculptures, pieces of jewelry and other artworks, totaling more than $20 million, had been in the Perls's custody but are unaccounted for, according to the Times.

A Swiss consignor referred to in Perls's records as "Madame Andre," the complaint maintains, turns out to have been a coded reference to a Swiss bank account Perls maintained. Perls's daughter asserts that Calder, too, had a Swiss bank account, but the estate tells the Times they have no evidence of any such holdings.

New Yorkers will soon have two opportunities to view Calder works in the flesh. Upper East Side gallery Venus Over Manhattan has announced an upcoming show of rare Calder sculptures, "Calder Shadows," including a "dozen rare Calder mobiles and stabiles created between 1929 and 1974" (Nov. 4-Dec. 21). The group exhibition "Show and Tell: Calder Jewelry and Mobiles," also including 10 other artists, will be at Salon 94 (Nov. 5-Dec. 20).

And, at the Los Angeles County Museum of Art, the show "Calder and Abstraction: From Avant-Garde to Iconic" is on view Nov. 24, 2013-July 27, 2014).