The period of the Consulate and the Empire was marked by the appearance of the first administrative codes, by the first syntheses which attempted to determine the principles of administrative science and administrative law. Their authors - Bonnin, Fleurigeon and Portiez de l’Oise - displayed an awareness that a new governmental and administrative order was being established in France. By comparing the principles drawn from these theoretical writings with the actual practice of the Imperial period, we can see how the administration was defined and legitimised in its new powers.