In connection with the expiration of the controversial witness protection law at the end of 1999, the question of under what conditions it is permissible and should be permissible to reward the informant activities of a witness with a sentence reduction has gained new relevance. Florian Jessberger approaches the figure of the witness from a sentencing law perspective. After outlining the complex legal situation and the significantly varying application practices depending on the type of offense, a review based on constitutional and criminal law systematic criteria reveals that certain provisions of German law are partially untenable, but the use of witnesses is not fundamentally incompatible with the system; rather, it is permissible within narrow limits. The extensive American experiences in dealing with witnesses are contrasted with the German legal situation.