The General Part
Title I
Criminal law and its application restrictions
Chapter I
Preliminary provisions
Legality of incrimination and of criminal law sanctions
Art.2 – (2) No one can be sanctioned for an act not provided in the law as an offence at the perpetration date, nor can a penalty be applied or a security or educative measure be taken that is not provided by the law in force at the perpetration date.
Non-retroactivity
Nulla poena sine lege
EDIT.