In 2019‑2020, 51% of the population aged 18 to 59 in metropolitan France said they had no religion. This religious disaffiliation has been increasing over the past ten years and concerns 58% of people with no migration background, 19% of immigrants who arrived after the age of 16 and 26% of the descendants of two immigrant parents. While Catholicism remains the dominant religion (29% of the population declare themselves to be Catholic), Islam confirms its place as the second religion in France (10%). The number of people claiming another Christian religion is also increasing, reaching 9%. The frequency and intensity of religious practice varies by religious affiliation: only 8% of Catholics regularly attend a place of worship, compared to just over 20% of other Christians, Muslims and Buddhists, and 34% of Jews. Processes of religious transmission between generations shape the religious landscape over the long term: 91% of people raised in a Muslim family follow the religion of their parents. This transmission is also very strong among Jews (84%), but less so among Catholics (67%) and other Christians (69%). All else being equal, growing up in a family of mixed religious or Catholic ancestry is a key factor in the secularization process among the descendants of immigrants.