77It is also settled case-law that, in the absence of any unifying or harmonising measures adopted by the European Union, the Member States retain the power to define, by treaty or unilaterally, the criteria for allocating their powers of taxation, particularly with a view to eliminating double taxation (Case C-540/07Commission v Italy [2009] ECR I-10983, paragraph 29 and the case-law cited, and National Grid Indus, paragraph 45). Such a justification can be accepted where, inter alia, the rules at issue are intended to prevent behaviour capable of jeopardising the right of a Member State to exercise its powers of taxation in relation to activities carried on in its territory (see, to that effect, inter alia, Marks & Spencer, paragraph 46; Rewe Zentralfinanz, paragraph 42; and National Grid Indus, paragraph 46).