Anyone summoned by a state court to be heard as a witness is in principle obliged to appear and testify (Section 380, 395 et seq. Code of Civil Procedure ZPO) and the courts can enforce that obligation. Things are different, however, in arbitration: There is no duty to appear before an arbitral tribunal. Read More
Peter Bert's Blog about Litigation, Arbitration and Mediation in Germany – Art Law, Case Law, News etc.