The word "narcotic" is often first associated with "illicit drugs". Yet, many "narcotic" and psychotropic substances are, in fact, medicines. Controlled medicines (CM) are products that meet the legal definition of both a "narcotic" under the Swiss Narcotics Act and of a medicine under the Therapeutic Products Act. We aim to examine how similar and how different, respectively, the implementation of CM regulations is throughout French-speaking Switzerland. Based on a legal analysis of the cantonal regulations, we conducted semi-structured interviews with cantonal pharmacists and cantonal physicians. We asked them how they perceive and implement the federal legal requirements. We find that some of these requirements have fallen into disuse, notably the federal duty to notify off-label use of CM. We observe that counterfoil prescriptions in their current paper format are a veritable data graveyard in the sense that they are not actively used to monitor or supervise the market. Moreover, we detect different conditions for opioid agonist treatment authorization. Some cantons require additional physicians' training or written commitments by the person treated. Our mapping of the CM regulation implementation can serve as a basis for cantons to review their practices.