“This sale is not just a business transaction but a homage to the Hopi Indians,” said Gilles Néret-Minet, the director of the house.

Historians say many Hopi artifacts were taken long ago by people who found them unattended in shrines and on altars along the mesas of the Southwest. Others were confiscated by missionaries who came to convert the tribe in the late 19th century. Some were sold by tribe members. But even those sales were not legitimate, Hopi leaders say, because they may have been made under duress, and because the tribe holds that an individual cannot hold title to its religious artifacts — they are owned communally.

The market for American Indian artifacts, both here and abroad, is robust, experts say, and auctions of Indian items in the United States typically proceed unimpeded by American law and unchallenged by most tribes. There are some protections, though, under United States theft statutes, experts say, as well as restrictions on the sale of pieces by museums and federal agencies.

The Hopis and their supporters say the Paris sale is especially objectionable because of its size and the religious significance of the items involved. They say it also illustrates a striking disparity between what the government is empowered to do to help a foreign country recover an object from the United States and its inability to do much to retrieve an American artifact for sale overseas.

When a nation like Italy or Cambodia claims ownership of an object in the United States, it typically invokes international accords that require American officials to take up the cases. The Justice Department, for example, recently sent two lawyers to Cambodia as part of an effort to help that country seize an ancient statue that Sotheby’s planned to auction in New York.