[...]

Whereas it is in the light of the foregoing considerations that the question of the so-called "control cordon" (cordon de surveillance) must be envisaged ; as France's right to have a police cordon at the political frontier of the zones has hardly been questioned by the Swiss Government ; as, on the other hand, the latter disputes the right of France to collect duties and taxes at this frontier, even if these charges are not duties on the importation or exportation of goods, but are duties and taxes which are also levied on the same articles produced or manufactured in France ; as such a restriction does not necessarily follow from the obligation contracted by France under the provisions of the treaties of 1815 and the other supplementary instruments relating to the free zones, and as, in case of doubt, a limitation of sovereignty must be construed restrictively ; as though it is certain that France cannot rely on her own legislation to limit the scope of her international obligations, it is equally certain that French fiscal legislation applies in the territory of the free zones as in any other part of French territory; as a reservation must be made as regards the case of abuses of a right, an abuse which however cannot be presumed by the Court;