Born in Paris in 1853, Mizon entered in the French Navy in 1869. Between 1880 and 1883 he was at Pierre Savorgnan de Brazza's orders, with whom he had difficulties working. In 1890 he was given the command of an expedition meant to find a viable route between the Niger and the Congo rivers by passing by the Benue and Sangha River. He also led a second mission in 1892 in the same places, meant in particular to establish French control over the Adamawa (in modern Nigeria), from which the Benue, the major tributary of the Niger, rises. The plan failed, for the English protested that the claimed territory had been assigned to Britain.