"We have accounts from an English tailor saying that his fabric came from Genoa, and that is the origin of jeans," said Gruber. "But this gives us new documentary proof of a historical reality that has been forgotten."
In a further quirk, the blue tint of the fabric was painted with the exact same indigo as that used to dye today's denim, according to curators.
Centuries later, husband and wife design team Francois and Marithe Girbaud earned a reputation as modern-day masters of the jeans world -- as pioneers of the baggy hip-hop look, of stonewashing or stretch denim.
"This calls into question the entire history we have been telling up until now," said Francois Girbaud, who partnered with the Paris exhibition. "And that's what's fun."
"In people's minds, jeans used to be all about Marilyn Monroe, James Dean, about the United States," he said. "Nimes or Genoa? I don't have the answer. But it's amusing to think that jeans already existed in 1655."
Ten paintings have been attributed to the Italian artist, eight of which are on show in Paris alongside works by contemporaries such as Michael Sweerts or Giacomo Ceruti, loaned from museums and private collections in Rome and Vienna.