How many Catholics live in France? The answer depends on what exactly is being measured. The most recent large-scale estimate suggests that approximately 43% of people aged 15 and over living in mainland France identify as Catholic. This figure comes from a major Ifop survey conducted in 2025 among more than 14,000 respondents. Applied to the population in that age group, it represents approximately 24 million people.
Another Ifop survey conducted the same year found that 46% of adults identified with Catholicism, while France’s national statistics institute (Insee) and the National Institute for Demographic Studies (Ined) reported a much lower figure of 29% among people aged 18 to 59 in 2019–2020. These seemingly contradictory results can largely be explained by differences in the populations surveyed and the questions respondents were asked.
France does not record the religious affiliation of its inhabitants in the national census. Available figures therefore come from representative surveys in which respondents identify their own religious affiliation. In a major survey conducted in 2025 among 14,244 people aged 15 and over living in mainland France, 43% declared themselves Catholic.
People reporting no religious affiliation accounted for 37.5% of respondents, Muslims for 7%, Protestants or Evangelical Christians for 4%, Orthodox Christians for 1%, Jews for 1%, and Buddhists for 1%.
What does the figure of 43% mean in absolute numbers? On January 1, 2026, mainland France had approximately 66.8 million inhabitants. Of these, around 10.7 million were under the age of 15, leaving approximately 56.1 million people aged 15 and over. Applying the 43% recorded by Ifop to this population produces an estimate of approximately 24.1 million self-identified Catholics.
However, this is not an official population count. It is a statistical extrapolation that excludes children under 15 and does not cover France’s overseas departments and territories. The appropriate conclusion is therefore that approximately 24 million people aged 15 and over identify as Catholic in mainland France, rather than presenting that number as a definitive count of all Catholics living in the country.
Another Ifop survey published in 2025 for the French Observatory of Catholicism reached a slightly higher estimate: 46% of people aged 18 and over said they belonged to Catholicism. The question, however, was worded differently. Respondents were asked which “religious denomination or school of thought” they considered themselves to belong to.
Such differences in wording illustrate why religious identity cannot be measured as straightforwardly as age or place of residence.
Age also plays a decisive role. In the same survey, only 23% of respondents aged 18 to 24 identified as Catholic, compared with 37% among those aged 25 to 34, 42% among those aged 35 to 49, 48% among those aged 50 to 64, and 62% among people aged 65 and over.
A survey that includes the entire elderly population will therefore naturally produce a significantly higher proportion of Catholics than one focusing on younger adults.
This partly explains the much lower estimate produced by the Insee-Ined Trajectories and Origins 2 survey. In 2019–2020, 29% of people aged 18 to 59 living in mainland France identified as Catholic. The survey excluded people aged 60 and over, precisely the generations in which Catholic affiliation remains most widespread.
Nevertheless, within that age group, Catholicism remained by far the largest declared religion, ahead of Islam at 10% and other Christian denominations at 9%.
The data reveal an even more significant development: a sharp decline in Catholic identification across generations. To compare the two waves of its survey accurately, Insee-Ined focused on the common age group of 18 to 49.
In 2008–2009, 43% of respondents in that age group identified as Catholic. Eleven years later, the proportion had fallen to just 25%. Over the same period, the percentage of people declaring no religious affiliation rose from 45% to 53%.
The transmission of Catholic identity within families remains important, but it is far from automatic. According to Insee-Ined, 67% of people raised in Catholic families still identify as Catholic in adulthood. Nearly one-third, 31%, report having no religion.
Direct conversions from Catholicism to another religion are much less common. Religious disaffiliation, rather than conversion, is therefore overwhelmingly the main factor behind the decline.
Identifying as Catholic does not necessarily mean practicing Catholicism.
The Insee-Ined survey found that only 8% of self-identified Catholics regularly attend church, defined as at least once a month. Another 18% attend mainly during religious holidays, while 68% go primarily for family ceremonies.
Only 15% also report praying at least once a week. Religion plays a very or fairly important role in the lives of 27% of Catholic respondents.
These figures show that Catholic identity in France often reflects a cultural or family connection rather than regular participation in religious life.
Baptism provides another way of measuring the historical influence of Catholicism.
The survey conducted for the French Observatory of Catholicism found that 76% of adults questioned said they had been baptized in the Catholic Church, a proportion far higher than the number who currently identify as Catholic.
Among those baptized, 66% said they never attend Mass. Another 28% attend a few times a year, 2% every Sunday, and 4% “as often as possible.”
The contrast is striking. Being baptized does not necessarily imply continued religious affiliation, regular attendance at Mass, or even belief in Catholic teachings.
Several distinct populations therefore exist within the broader Catholic heritage of France: people who have been baptized, those who currently identify as Catholic, those for whom their religious affiliation holds personal significance, and those who actively practice their religion.
Treating these different groups as if they represented a single, clearly defined population inevitably produces conflicting estimates.
The most cautious conclusion in 2026 is that approximately 43% of people aged 15 and over living in mainland France identify as Catholic, representing around 24 million people. Another major survey conducted in 2025 places Catholic affiliation at 46% among adults, while the Insee-Ined survey reports 29% among those aged 18 to 59.
These differences do not necessarily indicate uncertainty involving millions of people. Rather, they demonstrate that Catholic identification remains considerably more common among older generations, and that the term “Catholic” can refer to several different realities: declared religious affiliation, cultural identity, baptism, or active religious practice.
For a broader understanding of the country’s religious landscape, see our overview of Religion in France: Statistics and Trends in 2026, as well as our analysis of the Muslim population in France.