If a Member State does not respect EU law, the European Commission can start a so-called infringement procedure in order to make it comply.
These procedures are started either on the basis of an internal investigation by the Commission or following complaints from citizens, businesses or other stakeholders.
Enforcement of EU law is one of the core responsibilities of the European Commission's Directorate General for Taxation and Customs Union.
More information on the Infringement procedure
Commission decisions on Tax and Customs Infringements
Archive of cases before 2017
Ever since it was created, the European Court of Justice has been called on to deliver a huge number of judgments on customs and tax matters.
This wealth of cases has helped to clarify and elaborate the basic principles of the European Union in this area (freedoms safeguarded by the TFEU (Treaty on the Functioning of the European Union) and harmonised implementation of regulations and directives).
This is the latest list (12/12/2019) of Court cases in the field of, or of particular interest for, direct taxation
Details of cases can be obtained from the European Court of Justice Website.
The Commission cannot be held responsible for any mistake or oblivion on the informative list.