Admissibility of a strawman:

An opposition against a patent is possible in a term of 9 months after grant equally for a German or European patent.

Admissibility before the European Patent Office:

An opposition by a strawman is admissible according to G 3/97 and G 4/97. An exception to this principle is given if:

• the opposition is filed on behalf of the patent proprietor or
• the opponent offers services of legal advice without being a legal representative.

On the other hand, according to case law, an abusive circumvention of the law does not already exist if an authorized representative objects on behalf of a client in his own name.

Admissibility before the German Patent Office:

The BGH (German Supreme Court) decided in a nullity case in respect to a non-challenge clause. In this very special case the BGH came to the decision (10.07.2012 - Az. X ZR 98/11 - Strohmann) that a nullity case was admissible despite that non-challenge clause. However, a non-challenge clause may preclude admissibility if the strawman is bound by instructions, or the owner of the patent and the opponent are one and the same person in economic terms.