This week, thousands of households in France are turning on their heating systems after the summer, many following a rule they believe is a common-sense recommendation: heating to a maximum of 19 degrees Celsius. However, this is not just a suggestion—it is a legal obligation that has been in place for over fifty years. A decree from 1979 legally limits the average heating temperature in French homes to 19°C. This rule applies to the entire home as an average, not a strict limit per room. Certain groups, such as the elderly, children, and those receiving home care, can have their homes heated to an average of 22°C. While the law allows for fines of up to 1,500 euros for non-compliance, there are no actual inspections of private homes to enforce this rule. The rule was established in the context of an energy crisis during the 1970s, specifically under the Energy Savings Act of 1974. A few years later, a decree set the specific temperature limit and included it in the Building and Housing Code. The provision, outlined in Decree No. 79-907 of 1979, limits the average heating temperature to 19°C in homes, schools, offices, and public buildings. This regulation was introduced after the oil shocks of the 1970s, when energy conservation became a priority. Over the years, some lawmakers have called for the repeal of the decree, arguing that it is outdated now that oil prices have dropped. However, the government has consistently refused to change the regulation, citing the significant role that residential and commercial buildings play in national energy consumption. The law sets an average temperature for the entire home, not a strict limit for individual rooms. For example, a living room at 21°C, five bedrooms at 17°C, and a garage at 12°C would still meet the legal requirement. The key is that the average temperature across the home must not exceed 19°C. Certain groups, such as those living with elderly individuals, young children, or those receiving home care, are allowed to have a higher average of 22°C. However, even in these cases, the temperature in any single room must not exceed 24°C. These exceptions are outlined in a 1977 decree, which is nearly as old as the original regulation. While non-compliance with the temperature limit is technically a fifth-class offense, with a maximum fine of 1,500 euros, there are no actual inspections of private homes to enforce this. The government itself has acknowledged this during past energy-saving campaigns, stating that it is not practical to check every home’s temperature. As a result, the regulation exists on paper, but in practice, it is rarely enforced. This lack of enforcement has led to some homes, especially social housing, being underheated, despite legal exemptions for vulnerable groups. Many property owners and landlords are unaware of these exceptions, continuing to limit heating to the 19°C standard. The regulation itself, however, remains unchanged since the 1970s, despite calls for modernization.