Paul Pelliot
Vaillant travelled with Paul Pelliot and the photographer Charles Nouette on Pelliot's archaeological expedition to Eastern ("Chinese") Turkestan, modern Xinjiang, in 1906–1908. He was the expedition's doctor and also naturalist, acting on behalf of the Musée National d'Histoire Naturelle; progress was reported in the "Bulletin" of the museum by his father. This Pelliot–Valliant expedition was a successor to that of Jules-Léon Dutreuil de Rhins and Fernand Grenard of the 1890s.