his paper analyses the basis of African neo-constitutionalism and explores the intelligibility of the "new use" of the constitution in black Africa from the analysis of two cases of the constitutional trajectories: Mali and Chad. It puts into comparative perspective the experiences of regression or consolidation of the achievements of the democratic transitions carried out around 1990s. It grasps the constitutional traceability, breakdowns and continuities operated in neo-constitutionalism starting from the explanation and the correlation of the stages and components of this post-transition constitutional production, compared to the "original" constitutions, founders of the new African regimes. The understanding of the bases and the evolutionary path of neo-constitutionalism will help to understand not only the scope of certain structuring factors of this evolution but also the variables that condition these evolutionary trajectories.