Demographic ageing is one of the major challenges of the 21st Century. It directly raises the question of “Healthy Ageing”, a process allowing elderly persons to stay healthy and independent as long as possible. The role of the environment on this process arouses the interest of the scientific community: the influence of the environment on health can vary according to individuals and their behaviour. Taking into account the entanglement of these factors represents a challenge both on the theoretical level and on the methodological level. From this perspective, the purpose of this research consists of studying the relation between the residential environment of elderly persons and their Healthy Ageing and in examining if some behaviours, such as physical activity and social participation, play a role of mediation or interaction. So as not to limit the analysis to only one city or one country, two scales of analysis have been chosen: first, a group of European countries, and second, Luxembourg. In all these analyses, the residential environment is comprehended from the perceived characteristics of the neighbourhood of residence. The results show that some aspects of the residential environment, such as access to proximity services and social cohesion, are associated with Healthy Ageing. This research also shows that if the behaviours play an intermediary role between some residential environment aspects and Healthy Ageing (effect of mediation), persons who are physically and socially less active have a Healthy Ageing more vulnerable to the conditions of their residential environment (effect of interaction). ; Le vieillissement démographique est l’un des défis majeurs du 21ème siècle. Il pose directement la question du « Vieillissement en Santé », c’est-à-dire d’un processus permettant aux personnes âgées de rester en bonne santé et indépendantes le plus longtemps possible. Le rôle joué par l’environnement sur ce processus suscite l’intérêt de la communauté scientifique : l’influence de l’environnement sur la santé ...