Chazy was the son of a small provincial manufacturer and studied mathematics at the École Normale Supérieure with completion of the agrégation in 1905. He received his doctorate in 1910 with thesis Équations différentielles du troisième ordre et d’ordre supérieur dont l’intégrale générale a ses points critiques fixes. In 1911 he was maître de conférences for mechanics in Grenoble and then in Lille. In World War I he served in the artillery and became famous for accurately predicting the location of the German siege gun which bombarded Paris.[1] After the war he was again professor in the Faculté des Sciences de Lille (which later became the Lille University of Science and Technology). Simultaneously he taught at the Institut industriel du Nord (École Centrale de Lille). In 1923 he was maître de conférences at the École centrale des arts et manufactures in Paris (as well as examiner at the École polytechnique). In 1924 he became professor for mechanics and later for celestial mechanics at the Sorbonne, where he retired in 1953 as professor emeritus.
