Introduction – Promoting the new recommendations on physical activity (PA) and sedentary behavior is one of the key measures of French nutrition policy. The aim of this article is to describe awareness of these recommendations and the factors associated with it, and to analyze the links between adherence to the recommendations and awareness of them. For sedentary behavior, the study also presents the associations between behavior, perceptions of that behavior, and the perceived ability to change it. Method – This study is based on data from the 2021 Santé publique France Barometer, a survey conducted on a random sample of the population residing in France. The analysis focuses on 4,571 participants aged 18 to 75 who were asked about their knowledge of PA and sedentary behavior. Descriptive analyses and multivariate models were performed. Results – In 2021, awareness of the PA recommendation was partial: 96.7% of adults cited “at least 30 minutes of PA per day,” but fewer than one-quarter cited the correct recommended intensity. Overall, 21.6% of adults are aware of the full PA recommendation. An association between knowledge of the recommendation and adherence to it is observed only among women. The recommendation to break up sitting time at least every two hours is cited by 93.9% of respondents and is associated with following it. Three-quarters of adults believe it is recommended to break up sedentary time more often than every two hours. Spending more than seven hours sitting per day is associated with the perception of sitting too long during the day, without recognizing the possibility of reducing this high level of sedentary behavior. Conclusion – The low level of awareness regarding the recommendation on the intensity of daily physical activity highlights the need to communicate this concept in a more educational manner. The widespread belief that sedentary behavior should be interrupted more frequently than recommended suggests that a recommendation to this effect would be readily accepted. Recent scientific studies on the health benefits of breaking sedentary behavior every hour or half-hour are consistent and tend to call into question the recommended frequency of such breaks. Strategies to strengthen the perceived ability to reduce sedentary behavior should also be developed, in conjunction with environmental interventions.