30Finally, it must be stated that a provision such as that at issue in the main proceedings does not render impossible the exercise of the rights conferred by Regulation No 3427/89. It merely limits the retroactive effect of applications for the benefit in question (see the judgments in Case C-338/91Steenhorst-Neerings v Bestuur van de Bedrifsvereniging voor Detailhandel, Ambachten en Huisvrouwen [1993] ECR I-5475, paragraph 21, and Case C-410/92Johnson v Chief Adjudication Officer [1994] ECR I-5483).