This paper studies the subtle and attractive theory conceived by the famous French jurist Leon Duguit, founded in social considerations, that constituted in its moment, not only a juridical construction consequent with the consolidation of the rupture of the classic liberal economic model, but one of the most influent juridical and sociological theories in the indefatigable quest for a defining and justifying criteria of the substantivity of that Primary law that French revolutionaries, in clear dissent with the classical ideological postulates of the revolution, preached for their powerful public administration.