The expression “regulatory power” (or “regulating power”) is inherited from the French Revolution. As recurrent in constitutional law, it is a third body specifically responsible for ensuring the regular functioning of political institutions. First entrusted to an ad hoc body specially created for this purpose, regulatory power became the prerogative of an idealized constitutional monarch in the 19th century. Strictly confined to the institutional sphere and thus far from the government and partisan quarrels, the king would only be responsible for maintaining the active powers balance. The “neutral power” outlined by Benjamin Constant between 1800 and 1815 is undoubtedly the most famous theoretical translation of this doctrine. In contemporary constitutional law, the notion of regulatory power allows to qualify a specific legal function whose purpose is the correct and smooth functioning of the political system, understood as a complex system composed of various interacting bodies. If this system has a significant social function, which is the government, the regulation pursued by the regulatory power must be seen as an internal activity of an institutional system distinct from society. Many contemporary constitutions have chosen to entrust this mission to a specific authority: the regulator, which is independent of both the government and the political parties. In practice, two bodies, one political and the other jurisdictional, are entitled to this role: the Head of State and the Constitutional Court. Based on our doctoral dissertation defended in 2019, the aim of our paper is therefore to propose a kind of systematization of this particular role sometimes assigned by constitutional law to the Head of State or to the Constitutional Court. In contemporary democratic systems, the institutional imbalance in favor of the Executive often appears blatant. In France, the majority presidentialism that we have known without interruption since 2002 is based on uncertain foundations, to say the least, so much so that a major institutional crisis could arise at any time; the historical and comparative study of the structure and functioning of political power becomes all the more urgent.