1. A counterclaim for revocation or for a declaration of invalidity may only be based on the grounds for revocation or invalidity mentioned in this Regulation.
2. An EU trade mark court shall reject a counterclaim for revocation or for a declaration of invalidity if a decision taken by the Office relating to the same subject matter and cause of action and involving the same parties has already become final.
3. If the counterclaim is brought in a legal action to which the proprietor of the trade mark is not already a party, he shall be informed thereof and may be joined as a party to the action in accordance with the conditions set out in national law.
4. The EU trade mark court with which a counterclaim for revocation or for a declaration of invalidity of the EU trade mark has been filed shall not proceed with the examination of the counterclaim, until either the interested party or the court has informed the Office of the date on which the counterclaim was filed. The Office shall record that information in the Register. If an application for revocation or for a declaration of invalidity of the EU trade mark had already been filed before the Office before the counterclaim was filed, the court shall be informed thereof by the Office and stay the proceedings in accordance with Article 132(1) until the decision on the application is final or the application is withdrawn.
5. Article 64(2) to (5) shall apply.
6. Where an EU trade mark court has given a judgment which has become final on a counterclaim for revocation or for a declaration of invalidity of an EU trade mark, a copy of the judgment shall be sent to the Office without delay, either by the court or by any of the parties to the national proceedings. The Office or any other interested party may request information about such transmission. The Office shall mention the judgment in the Register and shall take the necessary measures to comply with its operative part.
7. The EU trade mark court hearing a counterclaim for revocation or for a declaration of invalidity may stay the proceedings on application by the proprietor of the EU trade mark and after hearing the other parties and may request the defendant to submit an application for revocation or for a declaration of invalidity to the Office within a time limit which it shall determine. If the application is not made within the time limit, the proceedings shall continue; the counterclaim shall be deemed withdrawn. Article 132(3) shall apply.