BOOK I
GENERAL PART
TITLE I
APPLICATION OF CRIMINAL LAW
SINGLE CHAPTER
GENERAL PRINCIPLES
Article 3. Applicability of criminal law over time
1. No person may be punished for an act defined as a crime at the time of its commission if a subsequent law no longer considers it as such.
2. In such a case, if a decision convicting the person has already been rendered, execution of said decision and its penal effects shall cease, even when the decision rendered is final.
3. The law subsequent to the commission of the crime shall apply to previous conduct whenever the same proves to be more lenient to the perpetrator and, in the case of a final decision, if any benefit may still be obtained.
EDIT.