Some 250 sacred Native American, Eskimo and pre-Colombian artefacts went under the hammer in France on Monday despite strong opposition from the Navajo and Hopi tribes who travelled to Paris to try to halt the sale. It was the fourth time in two years that sacred masks from the Hopi tribe have been sold at auction in France. The 18,000-strong Hopi tribe of Arizona uses the masks in dances at religious ceremonies that are normally closed to outsiders. The tribe and Survival International advocacy group did not protest the sale on this occasion, instead launching legal action to try to identify the buyers and sellers, according to their lawyer Pierre Servan-Schreiber. Representatives from another tribe, the Navajos, chose another route -- buying back their masks at a cost of 1,500 euros ($1,800). "We are happy to bring back with us these sacred masks that will be purified by