Additional grounds for invalidity

In addition to the grounds for invalidity provided for in Article 4, where appropriate with the exception of Article 4(1)(c) concerning signs or indications which may serve, in trade, to designate the geographical origin of the goods or services, and Article 5, a collective mark which is registered in breach of Article 31 shall be declared invalid unless the proprietor of the mark, by amending the regulations governing use, complies with the requirements of Article 31.