It is often said that proportionality is a method of ad hoc judicial reasoning. Close attention to practice however, exposes this vision as too simplistic. The content of proportionality is very different across jurisdictions, even in the application of the same legal text, and the role of concrete cases in judicial reasoning varies considerably. The purpose of this article is to illustrate this through a study of the reasoning of the French Council of State and of the European Court of Human Rights in the field of the Convention. The study of French and European proportionality case law reveals that different versions of proportionality involve different kinds of case-based reasoning, in which the case has a more or less normative function. The article suggests that this is connected to the local meanings of proportionality and of human rights in French law and in the Convention.