Masks from the Hopi, Zuni and Jemez tribes of the southwest United States will be for sale by the Neret-Minet Tessier and Sarrou auction house April 12, Radio France Internationale reported.
Most of the masks are from the Hopi tribe in Arizona. Hopi representatives said the masks were never supposed to leave the tribe.
Eric Geneste, an appraiser for the auction, said the masks came from a French collector and were part of a collection that included about 3,200 American Indian objects.
"This collection is a gift to humanity and to the Indian people, because over 30 years the collector has preserved these masks," he said. "The European and American collectors play the role of saviors. They preserved these objects, which will allow future generations of Hopi Indians to rediscover them in museums or institutions."
"These items ... were never meant to have any kind of commercial value," said Leigh Kuwanwisiwma, director of the Hopi Cultural Preservation Office.
Kuwanwisiwma said he believes the masks are authentic, but questioned whether the collector obtained them legally.
"We know that many items were taken from holding areas, what we call clan homes. These are ceremonial places where these items are kept. They were broken into, in many cases. Some were also stored in caves outside the villages," he said.
"No Hopi, under traditional law or under our modern law, has any right or authority to alienate these items. So, quite frankly, we have stated the position that these items have been collected illegally; they left the Hopi reservation illegally."
Historian Joelle Rostkowski said it is unlikely France will agree to give up the masks because non-French objects in France's museums are considered part of the French heritage.
"French law is very strict," she said. "Whatever is in our museums belongs to the French state."