PARIS: One of Picasso’s most unsettling paintings returns to Paris on Friday more than a century after he painted it in that city, as a taster for what is being billed the art “sale of the century.” One of the rarest Picasso paintings, once owned by Gertrude Stein, is part of an art trove belonging to the Rockefeller dynasty that could raise half a billion dollars this year, in what auctioneer Christie’s says could be the most valuable sale ever of a private collection. With the art market surging, the nude “Young Girl With a Flower Basket” is expected to make at least $100 million (81 million euros) when it goes under the hammer in New York in May along with works by Monet, Renoir and Gauguin from the private collection of US billionaires Peggy and David Rockefeller. Auction house Christie’s expects the sale of the 1,600 works of art amassed by the couple to top $600 million — easily beating the world record set in Paris in 2009 when the collection put together by the fashion designer Yves Saint Laurent and his partner Pierre Berge made $484 million. They include one of Monet’s waterlily paintings as a well as one of his famously smoky views of St. Lazare station in Paris and three Miro murals which are expected to fetch $25 million. “It’s a really historic moment, the biggest private collection ever put up for auction,” Christie’s French head Francois de Ricqles told AFP. It not only represents the works collected by “a couple of great taste,” he said, “but with the addition of the items they inherited reflects the passion of generations of the Rockefeller family for art.” David Rockefeller, the former head of Chase Manhattan Bank, died last year aged 101, two decades after his wife. The entire proceeds of the sale will go to charitable causes including Harvard University and conservation groups in the state of Maine, where the Rockefeller family had summer homes. The Picasso, a masterpiece from his pink period in 1905, is one of 10 works being shown by Sotheby’s in the French capital in the run-up to the sale. Once owned by Picasso’s friend, the American poet and novelist Gertrude Stein, it has not been shown in Paris in more than 50 years. Stein initially was troubled by the side-on view and the girl’s “repulsive” feet, but her husband Leo loved it. When they split up, however, she kept the painting for herself, leaving him their Cezannes. The Rockefellers were equally attached to it, not allowing it to leave their home on 65th Street in New York after they bought it in 1968. Selected works from the collection are being displayed around the world leading up to the sale. The Paris show also includes Georges Seurat’s picture of sailing boats, “La Rade de Grandcamp,” which is expected to make up to $30 million and Eugene Delacroix’s “Tiger Playing with a Tortoise” (1862), which has an estimate of $7 million.