In primo luogo, vi sono, come dimostrato nella parte sul ravvicinamento delle pene alternative, considerevoli differenze per quanto concerne la loro funzione e il loro carattere giuridico: in alcuni Stati membri, determinate pene alternative costituiscono pene principali o pene sostitutive, mentre, in altri, le stesse pene rappresentano misure collegate a pene detentive sospese.
First, as was seen in the section on approximation of alternative sanctions, there are considerable differences regarding their function and their legal nature: in some Member States, certain alternative sanctions are principal or substitute penalties, whereas in others, the same penalties are measures accompanying suspended prison sentences.