After the Second World War, clinical nephrology in Francophone countries had 4 leaders: in Paris, P. Vallery Radot with his assistants P. Milliez and J. Hamburger and their own groups; and also in Paris, M. Dérot with J. J. Bernier and M. Legrain; in Bruxelles, P. Govaerts with P. P. Lambert; and in Genève, R. Mach. To these one must add J. Traeger of Lyon and J. M. Suc of Toulouse who later joined the group. It all started in 1947-1948 around the Societé de Pathologie Rénale. In the current paper, the author describes the main 4 fields of development: water and electrolyte balance, acute anuria and dialysis, renal biopsy and classification of nephritides and finally transplantation under the direction of J. Hamburger and R. Küss both closely linked with J. Dausset and G. Mathé. These contributions had a broad impact on the history of modern clinical nephrology, which was acknowledged and crowned by the organization of the first Congrès International de Néphrologie by Hamburger and Mach, the development by which the specialty was acknowledged and the International Society of Nephrology (ISN) created with its first journal, Nephron. Hamburger, the first president of the ISN, had many difficulties to overcome to carry this goal through.