The exclusive rights of a trade mark proprietor and the interests of competitors and the general public in free trade require a compromise, so that in certain instances third party use of the trade mark cannot be prohibited. Such constellations are inter alia mentioned in Section 23 of the 1994 German Trade Mark Act, which permits the use of a third party's own name or address (number 1), the use of an indication concerning the characteristics or features of the goods or services (number 2) or where such use is necessary to indicate the intended purpose of a product, in particular as an accessory or spare part or a service, insofar as the use is necessary for it (number 3), provided the use is not contrary to the principles of morality.