Drawing on demographic data observed on a detailed territorial scale, the authors analyse the differentiated ageing of geographic spaces in France over the last forty years, taking account of the two dynamics (natural and migratory) driving the process. The clustering tools implemented – the results of which are presented in maps– bring to light unexpected littoral specificities, in particular on the French Mediterranean seaboard. Taking into account both the proportion of elderly people and their concentration in specific parts of the territory, the chapter shows that the rate of ageing is lower in urban than rural areas, a fortiori along the Mediterranean coasts, so that one can speak of ‘two Mediterraneans of French ageing’. The chapter underscores the major repercussions of the residential mobility of the populations at different stages of the life cycle for the ageing of the territories and, more broadly, the link between demographic ageing and the process of ‘littoralisation’. It confirms the value of territorially fine-grained demographic data in showing the dynamics of ageing in its territorial specificities and exceptions.