26It must be recalled, first of all, that in accordance with settled case-law, the subject-matter of an action under Article 258 TFEU for failure to fulfil obligations is determined by the Commission’s reasoned opinion, with the result that the action must be based on the same grounds and pleas as that opinion (see Case C-33/04Commission v Luxembourg [2005] ECR I-10629, paragraph 36; Case C-236/05Commission v United Kingdom [2006] ECR I-10819, paragraph 10; and Case C-171/08Commission v Portugal [2010] ECR I-6817, paragraph 25).