In the case of Byankov the Court of Justice ruled as follows: EU law must be interpreted as precluding legislation under which an administrative procedure that has resulted in the adoption of a prohibition on leaving the territory, which has become final and has not been contested before the courts, may be reopened - in the event of the prohibition being clearly contrary to EU law - only in circumstances such as those exhaustively listed in Article 99 of the Code of Administrative Procedure, despite the fact that such a prohibition continues to produce legal effects with regard to its addressee. This study discusses how the ruling can be placed in the case law of the Court that in accordance with the principle of legal certainty, EU law does not require that administrative authorities be placed under an obligation to re-examine a national final administrative decision.

This article examines the actual application of European administrative soft law in light of the Dutch principle of legality. European administrative soft law is not legally binding. However, European administrative soft law can generate judicial binding effects for the Member States on the basis of the jurisprudence of the Court of Justice. Moreover, the research on the actual application of administratice soft law in the field of European subsidies shows that it can also have a 'de facto' binding effect for the Member Sates.

The (legal and actual) binding effects of European administrative soft law are problematic in light of the principle of legality, according to which binding norms must be laid down in hard law. The article argues that with the application of administrative soft law, three functions of the principle of legality (the principle provides legal certainty and legitimacy and serves as a safeguard against public authorities) are not sufficiently met. Several possible solutions that may resolve this tension are proposed.