Professor Kastler spent most of his research career at the Ecole Normale Supérieure in Paris where he started after the war with his student, Jean Brossel a small research group on spectroscopy.
Over the forty years that followed, this group has trained many of young physicists and had a significant impact on the development of the science of atomic physics in France. The Laboratoire de Spectroscopie hertzienne  has then been renamed Laboratoire Kastler-Brossel in 1994 and has got a part of its laboratory in Université Pierre et Marie Curie  mainly at the École Normale Supérieure.