20 Finally, where a system like that created by the contested legislation applies rules to domestic products which differ from those applied to products imported from other Member States and lacks transparency and precision, the defendant government must furnish proof that the system of which the Commission complains could not in any circumstances have a discriminatory effect (see in that regard the judgments of the Court in Case C-152/89 Commission v Luxembourg [1991] ECR I-3141 and Case C-153/89 Commission v Belgium [1991] ECR I-3171).

59 In the Commission's submission, that apportionment of the burden of proof follows, moreover, from a principle, established in the case-law of the Court, according to which, where the Commission shows that it is entitled to entertain substantial and reasonable doubts as to the reliability of the controls carried out by the national authorities, it is for the Member State concerned to establish that those controls do not lead to an unjustified reduction in the amounts collected by the Communities as own resources (see, in particular, with regard to discriminatory levies, Case C-152/89 Commission v Luxembourg [1991] ECR I-3141 and Case C-153/89 Commission v Belgium [1991] ECR I-3171 and also, with regard to the guarantee section of the clearance of accounts of the European Agricultural Guidance and Guarantee Fund (EAGGF), Case C-247/98 Greece v Commission [2001] ECR I-1, paragraphs 8 and 9, and Case C-278/98 Netherlands v Commission [2001] ECR I-1501, paragraphs 40 and 41).