There are no government statistics for churchgoers as it is regarded as counter to freedom of choice to ask anyone about their religious beliefs. Any information that exists, therefore, comes from opinion polls.
In 2017 a survey for La Croix Catholic newspaper, showed 1.8% of the population went to Mass every Sunday.
This is down from a similar 2009 study showing 4.5% went to Mass, while in 1952 some 27% were weekly churchgoers.
In Spain by comparison, about 20% of the population go to Mass once a week.
Statistics from the Catholic church also reflect this downturn. The number of baptisms has decreased from nearly half-a-million in 1990 to just over a quarter-of-a-million in 2015.
In the same period the number of confirmations has halved and church weddings have more than halved.
Just after the Second World War an early Ifop poll found eight out of 10 people said they were Catholic. By 2016 this figure had dropped to 64%, mainly made up of people who identify with the church even if they were not regular practitioners.
A Gallup poll in 2009, found 30% said the religion was an important part of their lives.
It is thought that between seven and 10% of the population are Muslim in France and 2% are Protestant.
In terms of the numbers who say they are Catholic, rather than the numbers who go to church, Catholicism remains the number one religion, but whether it is still a Catholic country is open to debate.