In 1931 Ylla moved to Paris to continue her studies at the Académie Colarossi and supported herself by working with the photographer Ergy Landau as assistant and photo retoucher. The following year, after impressing Landau with several photographs she had taken of farm animals while on vacation in Normandy, Ylla began to consider foregoing sculpture for photography. Landau soon arranged an exhibition for Ylla at Galerie de La Pléiade, a vanguard scene quickly gaining prominence for promoting the current wave of photography to its select and informed public. Her exhibition was well received, such that Landau encouraged Ylla to open the first studio in Paris specializing in animal portraits. Landau was Ylla's entrée to the artistic milieu of Montparnasse; she introduced Ylla to Charles Rado of the RAPHO photo agency, who immediately began to promote her internationally in the world of publishing. Her photographs first appeared in several annual editions of Photographie, published by Arts et Métiers Graphiques, and Lilliput in England. In 1936, Ylla participated in the Exposition internationale de la Photographie contemporaine at the Musée du Louvre, the first photography exhibition to take place in a state museum – nine Ylla photographs were exhibited. In 1937, the Museum of Modern Art (MoMA) in New York, included three Ylla photographs in its retrospective Photography 1839–1937. The same year, Ylla published two small collections of dog and cat photographs, followed in 1938 by her first major book, Petits et Grands (published as Big and Little in England and the United States). That same year she collaborated with British evolutionary biologist Julian Huxley for his new book, Animal Language, which included two records of animal calls.
Source: http://www.pryordodge.com/ylla