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Protective letters for German courts and the Unified Patent Court

To enable proprietors of a patent in force in Germany to effectively protect their rights under the patent, they can apply for injunctions against alleged patent infringers as a means of interim legal protection. Injunctions can, for example, be aimed at prohibiting an alleged patent infringer from distributing or manufacturing a certain patent-infringing product within the area where a patent (injunction patent) is valid on pain of a fine or imprisonment.

The effectiveness of interim legal protection is expressed, among other things, by the fact that the competent court can issue the injunction without first hearing the alleged patent infringer. In order to nevertheless also protect the rights of the alleged patent infringer, whose product is only allegedly a patent infringement and therefore may also be considered not interferring with the scope of protection of the injunction patent, German and European law foresees the means of a protective letter as a possible defense measure.

The purpose of a protective letter is therefore to present arguments to a court, which has to decide whether to issue an injunction, that speak against issuing the injunction.

An injunction is issued if an applicant for an injunction credibly substantiates a claim for an injunction and urgency (grounds for an injunction).

The content of a protective letter in the patent system is accordingly aimed at

  • denying a claim for an injunction by
    • challenging the legal validity of the injunction patent and/or
    • challenging the facts of infringement and/or
    • objecting to the enforcement of the injunction patent (e.g. exhaustion or right of prior use),


  • denying the urgency.

As with the application for an injunction, the reduced standard of proof of prima facie evidence in interim legal protection also applies to the corresponding protective letter.

The place of filing of a protective letter depends on the type of injunction patent.

With regard to German patents and German parts of European patents for which the lack of jurisdiction of the Unified Patent Court (UPC) has been requested (opt-out request), protective letters must be filed in the German central electronic register of protective letters (ZSSR).

With regard to European patents for which no opt-out request has been filed and European patents with unitary effect (unitary patents), protective letters must be filed directly in the UPC’s case management system.

Since opt-out requests can be withdrawn at any time, it may also make sense to file a protective letter with the UPC for European patents for which an opt-out has been requested to date.

With regard to protective letters for the UPC, it should be noted that the area where the injunction patent is valid usually extends beyond Germany, so that non-German companies that are at risk of being affected by an injunction should also be mentioned in the protective letter. Protective letters for the UPC must also be drafted in the language of the proceedings of the injunction patent and can therefore be in English, French or German.

If you suspect that competitors could wrongly accuse you of patent infringements, so that the issuance of injunctions is imminent, we will be happy to support you in defending yourself by means of protective letters.

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