PRELIMINARY TITLE
On penal guarantees and on the application of the Criminal Law

Article 2

1. No felony or misdemeanour shall be punishable by a punishment that is not foreseen by Law prior to it being committed. Likewise, the Laws establishing security measures shall not have retroactive effect.

2. Notwithstanding this, criminal laws that favour the person found guilty shall have retroactive effect, even though final judgement may have been handed down and the convict is serving a prison sentence at the time of them coming into force. When doubt arises in determining the most favourable law, the prisoner shall be heard. However, offences committed while a temporary Law is in force shall be judged pursuant thereto, except for express provisions to the contrary.

PRELIMINARY PART

Article 9

3. The Constitution guarantees the principle of legality, the hie¬rarchy of legal provisions, the publicity of legal enactments, the non-retroactivity of punitive measures that are unfavourable to or restrict individual rights, the certainty that the rule of law will prevail, the accountability of the public authorities, and the prohibition against arbi¬trary action on the part of the latter.