A Zurich-based lawyer has claimed that a painting in his collection, Madonna Leo X, is an original by Renaissance master Raphael, according to German daily Die Welt. The lawyer, Hanspeter Sigg, suggests that a similar picture, La belle Jardinière, which hangs in the Louvre is, in fact, a replica of his painting.

Sigg is said to have put his painting through a series of tests, the last of which allegedly confirmed that the painting was created in the 16th century. However, according to the paper, Sigg has not taken the picture to any laboratory that would be able to definitively determine whether his painting is indeed a Raphael or simply the work of the master’s studio or a later imitator. Any X-ray or infrared studies of the image, if they have been performed, remain unpublished.

The work is no flea market find. Madonna Leo X is well documented in Raphael literature as a copy of the Louvre’s La belle Jardinière. The Louvre painting is estimated to have been created in 1507-1508.  Madonna Leo X has been in Sigg’s family for five generations, having been acquired in the mid-1800s, and is currently held in a safe in Zurich. Few have ever laid eyes on the painting, however, Sigg’s family never having loaned it out for exhibitions.

According to Sigg, however, the Louvre’s version of the image was painted after his. He says it was a copy made by the Giulio Romano-led Raphael studio for France’s King Francis I. Sigg’s Madonna, so he says, was painted in 1513 for Pope Leo X, a member of the storied Medici family of art patrons.

The claims should be taken with a formidable grain of salt, however. Only last year, an art historian in Frankfurt argued that the portrait of Pope Julius II that he had recently acquired was the work of Raphael rather than a copy. Forty years earlier, the version of the painting believed to be “real” swapped from the version hanging in Florence’s Uffizi Gallery to that of the National Gallery in London. Until further testing is published, no new conclusions can be drawn.