PARIS -- There's something vaguely familiar about this charcoal sketch of a woman's face and nude torso — could it be an unclothed precursor to the Mona Lisa?

French government art experts are trying to find out, analyzing the sketch in a laboratory beneath the Louvre Museum to see if Leonardo da Vinci himself drew it before painting his 16th-century masterpiece.

The sketch, previously attributed to da Vinci's students, is part of a collection at the Musee Conde du Domaine de Chantilly museum north of Paris. Museum curator Mathieu Deldicque said on BFM television Friday that there are signs that it was painted by da Vinci himself.

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The Mona Lisa oil painting, among the world's greatest art treasures, hangs in the Louvre.