Introduction: Physical inactivity in children and adolescents is associated with poor physical ability and increased morbidity and mortality in adulthood, among other health problems. Currently, three in four adolescents are not physically active enough and fail to meet the recommended amount of exercise set by the WHO. The low rates not only show a concerning lack of physical activity (PA) among young people globally, but also sedentary behaviours seem to become omnipresent in their lives. In order to have a better understanding of the current situation, this paper undertakes an analysis of the lack of PA and sedentary lifestyles tendencies among French children and adolescents. Methods: Methodologically, this study uses a literature review approach to highlight factors responsible for such behaviours, and focuses on the situation in France. Previous and new scientific studies conducted by experts and researchers in the field of health and sport were used to have a better understanding of the different factors and consequences of physical inactivity, and solutions were suggested to tackle the issue. Results and Conclusions: Despite not being an isolated case, insufficient funding, efforts and strategies reinforce difficulties to efficiently tackle physical inactivity, leading to growing health concerns in France. Therefore, it is important to raise awareness of the adult population about this growing issue, as there should be more qualified professionals and experts working on education and knowledge, role modelling, encouragement and counselling in PA. Moreover, regional and local authorities should encourage the construction of safe play areas that provide access to outdoor play areas, especially in bigger cities. By promoting exercise integration and sport participation - essential to children's everyday life - we can minimize health problems that can occur later and help young people develop healthy habits and lifestyles.