Sports mega-events (SME), such as the Olympic and Paralympic Games (OPG), involve substantial financial investments and have long-term economic, social and health impacts. Despite their potential to promote health and well-being, evidence on their legacies remains inconclusive. The Paris 2024 OPG adopted a Health Impact Assessment (HIA) approach to evaluate its effects and optimize its legacy. Approach/Results: The HIA of the Paris 2024 OPG, conducted between 2016 and 2017, examined key health determinants related to physical activity, employment and environmental conditions. The findings informed the city's legacy strategy, influencing policies on active mobility, social inclusion and sustainable urban planning. However, challenges such as data limitations and a lack of systematic participatory methods were noted. Conclusion: The Paris 2024 HIA demonstrated the value of integrating health considerations into SME planning. Future events should adopt more comprehensive frameworks for assessing long-term legacies, ensuring equitable benefits for all population groups.