According to the Energy Code of France, residential buildings must not have an average temperature above 19° C in rooms and areas used for purposes other than housing within the same building (Article R. 241-26). This regulation aims to promote energy efficiency and reduce overall energy consumption. If this limit is exceeded, the law theoretically allows for a fine of 1,500 € for a fifth-class contravention, which could be doubled to 3,000 € if the violation occurs again (Articles R. 241-29-1 of the Energy Code and 131-13 of the Penal Code). However, the interpretation and enforcement of this rule remain unclear. In an interview with the Agence France-Presse (AFP) on October 12, 2022, lawyer Arnaud Gossement explained that while the law suggests a potential sanction, it is not currently enforceable in practice. He noted that the wording of the regulation is too vague to be applied effectively in homes. The lack of clear procedures for detecting and measuring violations has left the law in a legal gray area. As a result, it is unclear how or if the rule would be enforced in real-world situations. The 19° C threshold is described in a brochure by the Agency for the Environment and Energy Management (Ademe) as a measure to ensure comfort and support the principle of "energy sobriety," which encourages the responsible use of energy. However, the brochure also emphasizes that compliance with this temperature limit is not mandatory. Individuals are free to choose whether to follow the guideline or not, and the regulation does not impose strict obligations. This legal ambiguity reflects broader challenges in implementing environmental policies at the individual level. While the goal of reducing energy use is widely supported, the practical enforcement of such regulations remains difficult without clear definitions and monitoring mechanisms. As a result, the 19° C rule is more of a recommendation than a binding requirement, leaving its impact on energy consumption uncertain.