The police are obliged to report every offence to the public prosecutor's office (cf section 163 of the Code of Criminal Procedure, StPO). As a rule, prosecution is mandatory for the public prosecutor as well. This corresponds to the German "principle of mandatory prosecution" (sections 152, 160 of the Code of Criminal Procedure). However, the penal law includes special provisions which allow the public prosecutor, in exceptional instances, to refrain from prosecution ("principle of discretionary prosecution"). Provisions relating to this principle of discretionary prosecution in the Narcotics Act are sections 29 subs. 5 and 31a, in the Code of Criminal Procedure particularly sections 153, 153a to 153e as well as section 154.