Real or fake? A copy of da Vinci's Mona Lisa sells for $611,950 at auction
The 17th-century copy was initially valued at 70,000-90,000 euros.
The Mona Lisa itself, on which da Vinci began work in 1503, has hung at the Louvre Museum in Paris for more than 200 years. It is thought to depict Lisa Gherardini, the wife of a Florentine silk merchant, Francesco Giocondo.
"This amazing result testifies to the power of the lasting fascination of this iconic painting," Baukje Coenen, a director at Sotheby's, said in a statement about Tuesday's sale.