Article 13 of the Convention of 27 September 1968 on Jurisdiction and the Enforcement of Judgments in Civil and Commercial Matters is to be interpreted as meaning that a plaintiff who is acting in pursuance of his trade or professional activity and who is not, therefore, himself a consumer party to one of the contracts listed in the first paragraph of that provision, may not enjoy the benefit of the rules of special jurisdiction laid down by the Convention concerning consumer contracts.