Article 91

In addition to the grounds for revocation provided for in Article 58, the rights of the proprietor of an EU certification mark shall be revoked on application to the Office or on the basis of a counterclaim in infringement proceedings, where any of the following conditions is fulfilled:
(a) the proprietor no longer complies with the requirements set out in Article 83(2);
(b) the proprietor does not take reasonable steps to prevent the EU certification mark being used in a manner that is incompatible with the conditions of use laid down in the regulations governing use, amendments to which have, where appropriate, been mentioned in the Register;
(c) the manner in which the EU certification mark has been used by the proprietor has caused it to become liable to mislead the public in the manner referred to in Article 85(2);
(d) an amendment to the regulations governing use of the EU certification mark has been mentioned in the Register in breach of Article 88(2), unless the proprietor of the mark, by further amending the regulations governing use, complies with the requirements of that Article.