Politi SAS. v Ministry for Finance of the Italian Republic (Case 43-71)  ECR 1039.
8. The Court is next asked whether the provisions of Articles 14 (1) and 18 (1) of Regulation No 20, as well as the first indent of Article 17 (2) and the first indent of Article 19 (1) of Regulation No 121/67 are immediately applicable within the national legal system and, as such, create individual rights which national courts must protect.
9. Under the terms of the second paragraph of Article 189 regulations 'shall have general application' and 'shall be . . . directly applicable in all Member States'.
Therefore, by reason of their nature and their function in the system of the sources of Community law, regulations have direct effect and are as such, capable of creating individual rights which national courts must protect.
The effect of a regulation, as provided for in Article 189, is therefore to prevent the implementation of any legislative measure, even if it is enacted subsequently, which is incompatible with its provisions.