This paper explores the constitutional dimension of comparative criminal law procedure in a European context. It does so by focusing on the European civil law traditions and by explaining how the impact of constitutional law reasoning has changed the criminal law landscape. The paper argues that the influence of European Union law and the European Convention on Human Rights regime together with other comparative law effects have led to an adapted version of the comparative law project, where the orthodox distinction between civil law and common law is largely erased. Specifically, the paper focuses on the question of fairness and justification in the criminal law process, the principle of proportionality and the notion of dignity in a comparative perspective. The paper draws on both doctrinal and theoretical examples.