PART TWO
HUMAN AND MINORITY RIGHTS AND FREEDOMS
1. Fundamental Principles
Legal certainty in criminal law
Article 34
No person may be held guilty for any act which did not constitute a criminal offence under law or any other regulation based on the law at the time when it was committed, nor shall a penalty be imposed which was not prescribed for this act.
The penalties shall be determined pursuant to a regulation in force at the time when the act was committed, save when subsequent regulation is more lenient for the perpetrator. Criminal offences and penalties shall be laid down by the law.
Non-retroactivity
Nullum crimen sine lege
Nulla poena sine lege
EDIT.