The dynamics of the principle of proportionality.

Summary The impact of the principle of proportionality throughout the world is one of the most significant legal developments of recent years and explains the considerable interest that this question has aroused in the French and international literature. In contrast to analyses that tend to trivialize its impact (notably by reducing it to the rank of a mere exception to the normal functioning of the legal system), this thesis seeks to show that the principle of proportionality signifies a profound upheaval of the law. The analysis is approached in the particular context of the European Union, which proves to be paradigmatic in many respects, from an examination of the reasoning of the Court of Justice in its decisions in application of the freedoms of movement. The interest of this examination is twofold. On the one hand, it makes it possible to take note of the extent of the transformative potential of the principle of proportionality on the formal level (imposing a form of factualized reasoning, which consists of a cost-benefit evaluation), on the material level (setting up the efficiency of state measures as the ultimate goal of the freedoms of movement) and on the institutional level (redefining the distribution of competences between the Union and the Member States). On the other hand, as the principle of proportionality is a mirror particularly apt to reflect the legal culture of the Union, this examination also allows us to identify the characteristic features of this culture, to show in particular the prevalence of a discourse of a technocratic nature (Editor's summary).