Can. 16

§1. The legislator authentically interprets laws as does the one to whom the same legislator has entrusted the power of authentically interpreting.

§2. An authentic interpretation put forth in the form of law has the same force as the law itself and must be promulgated. If it only declares the words of the law which are certain in themselves, it is retroactive; if it restricts or extends the law, or if it explains a doubtful law, it is not retroactive.

§3. An interpretation in the form of a judicial sentence or of an administrative act in a particular matter, however, does not have the force of law and only binds the persons for whom and affects the matters for which it was given.