By the end of 1934 Sonia was working on designs for the 1937 Exposition Internationale des Arts et Techniques dans la Vie Moderne, for which she and Robert worked together on decorating two pavilions: the "Pavillon des Chemins de Fer" and the "Palais de l'Air". Sonia however did not want to be part of the contract for the commission, but chose to help Robert if she wanted. She said "I am free and mean to remain so." The murals and painted panels for the exhibition were executed by fifty artists including Albert Gleizes, Léopold Survage, Jacques Villon, Roger Bissière and Jean Crotti.