The period of the Consulate and Empire was marked by the appearance of the first administrative codes, the first syntheses aiming to establish the principles of an administrative science and an administrative law. The authors of these codes – Bonnin, Fleurigeon or Portiez de L’Oise – displayed an awareness of a new governmental and administrative order then being established in France. By comparing the principles found in these theoretical writings with the actual practices in effect during the Imperial era, it is possible to see how the administration was defined and legitimized in its new powers.