The trial is Germany's largest so far in the tentacular diesel scandal, which last week saw VW chief executive Herbert Diess charged with market manipulation over his role. In the mass lawsuit, the most important of around 50 questions for judges is whether Volkswagen "caused harm" by acting "dishonestly". Klaus Mueller of VZBV said he is "convinced" the car firm did, while VW says "clients did not suffer harm". "Hundreds of thousands of cars are used" on the roads without a problem, VW lawyer Martine de Lind van Wijngaarden said. Even if judges find in favour of plaintiffs, there will not be an immediate compensation payment. Rather, every owner registered in the trial will have to claim individually.