Eugène Delacroix's masterpiece Liberty Leading the People was attacked last night with a magic marker. A young woman vandalized the canvas with a slogan thought to refer to a 9/11 conspiracy theory.

The museum has said the damage to the canvas, from 1830, is superficial and that the work should be easily cleaned, according to L'Express. It was hanging in the Louvre Museum's recently opened branch in Lens.

The woman wrote "AE911" on the canvas, which many in France suspect is a reference to "Architects and Engineers for 9/11 Truth," a group that suspects that the 9/11 attacks were an inside job. The vandal's identity has not yet been revealed, and she has been reported to be 28 or 29 years old by different sources.

The painting shows a bare-breasted female figure bearing aloft the French Tricolor with one hand and a musket in the other. It is a national symbol for the French Revolution and long adorned the country's 100-franc note.

The attack comes less than two months after a young Polish man vandalized a Mark Rothko canvas at Tate Modern, London, with a slogan pertaining to an art movement, "yellowism," that he cofounded.