Following his divorce, Mr Schempp, a German national resident in Germany, pays maintenance to his former spouse resident in Austria. In his tax declarations , Mr Schempp sought to deduct the maintenance payments, in accordance with the first and second sentences of Paragraph 1a(1)(1) of the German EStG. However, in his income tax assessment, the Finanzamt refused to allow him the deduction on the ground that it had not received a certificate from the Austrian tax authorities to show that his former spouse had been taxed in Austria on the maintenance payments, as prescribed by the third sentence of Paragraph 1a(1)(1). Mr Schempp was unable to produce such a certificate, as Austrian tax law excludes, in principle, taxation of maintenance payments and does not allow them to be deducted. The German Bundesfinanzhof (Federal Tax Court), taking the view that the proceedings raised questions of interpretation of Community law, decided to stay the proceedings and refer the question whether the German tax rules infringe Art 12 and Art 18 EC to the Court for a preliminary ruling. Michael Lang analyses the ECJ's decision critically and concludes that the ECJ is changing its case law.