The authors believe that the C. Schmitt’s notion of unconstraint sovereignty is not flawless. Both A. Dicey’s theory of British constitutional law and the international human rights instruments have required the measures of the derogation of human rights must be given in accordance with proportionality principle. However, these normative requirements have hardly been applied to the judicial scrutiny by the two supranational courts in Europe. Correspondingly, some European public authorities favour the more radical precautionary principle. Although this principle is more effective in suppressing the new coronavirus, it is associated with numerous side effects. Thus, the authors propose in this article an innovative concept of precautionary proportionality principle.