This book examines the interface between EU primary law and national substantive and procedural legislation governing fines imposed by Member States for breaches of European law or national implementing legislation. It focuses on analyzing the general principles of EU law and the European fundamental rights enshrined in the Charter of Fundamental Rights of the European Union. It explains the links between EU law and national fining legislation or proceedings that trigger the duty to respect EU primary law. It covers the concepts of consistent interpretation, the primacy of EU law, and the effectiveness of European fundamental rights and general principles from the perspective of national fining proceedings and the protection of individuals. The collection discusses the following principles and fundamental rights: the principle of legal certainty, the principle of protection of legitimate expectations, the principles of equal treatment and non-discrimination, the principle of proportionality, the principle of ne bis in idem, the principle of good administration, and the right to an effective remedy. Each principle or fundamental right has been analyzed coherently, with the focus on the rights of individuals and the duties of national administrative authorities and courts in the course of national fining proceedings. It also explores the interdependencies between various principles and rights, as well as some specific problems in this area that have occurred in Poland, thus showing the practical importance of the research, or issues that are common to all Member States irrespective of differences in national procedures and fining provisions. The volume will be a valuable resource for researchers, academics, and policy-makers working in the areas of EU law, Administrative Law, and Comparative Law.