The 70 objects, mainly Hopi, went on display at Drouot for the first time as the court battle kicked off on Thursday, offering a rare public glimpse of such works in Europe. They date from the late 19th century and early 20th century, and are thought to have been taken from a northern Arizona reservation in the 1930s and 1940s. The most expensive single mask is estimated to be worth at least €50,000 (£43,000).

The masks are striking – surreal faces made from wood, leather, horsehair and feathers, painted in vivid pigments of red, blue, yellow and orange. Hopi representatives contend the items were stolen at some point and wanted the auction house to prove otherwise.

Disputes over art ownership, demands for restitution, and arguments over whether sacred objects should be sold are nothing new.

There has been a decades-long dispute between the British Museum and Greece over the Parthenon marbles, which Scottish diplomat Lord Elgin removed from the Parthenon in the 19th century. Greece wants them back but opponents fear that would open the floodgates, forcing western museums to send home thousands of artefacts.