With regard to the application of penal provisions to conduct engaged in before this Act (or, for the provisions prescribed in the proviso to Article 1 of the Supplementary Provisions, those provisions; the same applies hereinafter) comes into effect and to conduct engaged in after this Act comes into effect in the case where the provisions then in force are to remain applicable pursuant to the provisions of Article 2, paragraph (3) and Article 4, paragraph (1) of the Supplementary Provisions, the provisions then in force continue to govern.