An original equipment manufacturer has marked packages of ink cartridges with different signs like a teddy bear, a duck or an umbrella. The purpose was to facilitate, for the user, the classification of a certain ink cartridge to a certain printer. The original equipment manufacturer filed suit on the basis of unfair competition allegations against a competitor for using basically identical signs for matching ink cartridges. Unlike the first and second instance the German Federal Supreme Court rejected the action. The court denied that there is an unfair free riding. The signs have the function of product numbers which also can be referred to in a comparative advertisement without violating unfair competition standards.