TITLE I
PERSON AND SOCIETY
CHAPTER I
FUNDAMENTAL RIGHTS OF THE PERSON
Article 2
d. No one shall be prosecuted or convicted for any act or omission which was not previously prescribed in the law, expressly and unequivocally, as a punishable violation, or did not constitute an offence penalized by law.
Nullum crimen sine lege
Nulla poena sine lege
EDIT.