Central place theory has « obsessed » geographersduring the past50years. The contours of the christallerian « dogma » are considered, and research in this tradition is assessed. Central place theory focusses on the centrality of urban functions. The concentration of population within urban networks must also be considered and, in particular, the long term evolution of the distribution of cities according to size. An index of hierarchical structuration is used here to this end. The index isapplied to the evolution of the French urban structure between 1831 and 1911.