Katsinam

In April 2013 a Paris court let 70 Hopi katsina masks be sold, ruling it could protect only human remains or living beings.

Archaeology (Archaeological Institute of America), 12 April 2013; NBC News, 12 April 2013

Hopi and Pueblo spirit beings, personated by masked dancers and represented by carved dolls.

Sources4 sources

Primary source

J. Walter Fewkes, Hopi Katcinas Drawn by Native Artists, 1903, section on the nature of katcinasKatsinam as ancestral spirits, personated by men and represented by carved dolls.
The katcinas are spirits of the ancients of the Hopis

Scholarship

Archaeology magazine, Native American Artifacts Sold in France, 2013, 12 April 2013A Paris court let the April 2013 sale of 70 Hopi masks proceed despite the tribe's appeal.
the judgment recognizes that these masks have a sacred value
NBC News (Reuters), Hopi masks snapped up after French court allows auction, 2013, 12 April 2013Grounds on which the Paris court rejected the Hopi and Survival International motion.
it could only intervene to protect human remains or living beings

The tradition itself

United States Court of Appeals, Ninth Circuit, Navajo Nation v. United States Forest Service, 479 F.3d 1024, 2007, Part I.B.1 (The Hopi)The Hopi record: katsinam are ancestral spirits living on the San Francisco Peaks, appearing as clouds and bringing rain.
From July through January, the Katsinam live on the Peaks.