PART III
BASIC RIGHTS AND DUTIES
The Right to Equality
13. Equality before the law
(6) To ensure equality before the law, the state authority shall make procedures which are appropriate or which take into account the following principles, namely :
(c) no person shall be punished for any act which at the time of its commission was not an offence under the law, and also no penalty shall be imposed which is heavier than the penalty in force at the time the offence was committed ;
Nullum crimen sine lege
Nulla poena sine lege
EDIT.