Section 9 (...) (3) The Constitution guarantees the principle of legality, the hierarchy of legal provisions, the publicity of legal statutes, the non-retroactivity of punitive provisions that are not favourable to or restrictive of individual rights, the certainty that the rule of law shall prevail, the accountability of public authorities, and the prohibition of arbitrary action of public authorities.
Section 25(1) No one may be convicted or sentenced for actions or omissions which when committed did not constitute a criminal offence, misdemeanour or administrative offence under the law then in force. (2) Punishments entailing imprisonment and security measures shall be aimed at reeducation and social rehabilitation and may not involve forced labour. The person sentenced to prison shall enjoy, during the imprisonment, the fundamental rights contained in this Chapter except those expressly restricted by the content of the sentence, the purpose of the punishment and the penitentiary law. In any case, he or she shall be entitled to paid work and to the appropriate Social Security benefits, as well as to access to cultural opportunities and the overall development of his or her personality. (3) The Civil Administration may not impose penalties which directly of indirectly imply deprivation of freedom.