Like most European countries, has a colorful history of Catholics and Protestants massacring each other for hundreds of years. We owe secularism to these conflicts, which began from the conflict between corrupt church officials and kings over who should rule. https://en.wikipedia.org/wiki/French_Wars_of_Religion
In the late 18th century the Catholic church was as usual, enormously corrupt. The church also stood with the corrupt aristocracy. Napoleon tried to fix the problem.
First he tried to dechristianize France, weakening the power of the Catholic church which ran the state in conjunction with the aristocracy. (Long ago certain kings have been known to appoint popes, and pope were king-makers.) Napoleon seized vast church estates and their assets to finance the revolution.
Then Napoleon compromised with the Pope and restored church powers with state oversight so certain Christians would stop rebelling and massacring. He extended this partnership into conquered countries, and it is to this short lived Age of Reason that we owe the secularism of France.
Napoleon said in April 1801, “Skillful conquerors have not got entangled with priests. They can both contain them and use them.”
His quote mirrors an old adage from Seneca in Rome some thousand years prior, “Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful.”
Even now contemporary Republican presidents tap into religious psyche to win popularity with the masses. Long live the timeless partnership between chieftains and the witch doctors! Politics and religrelated:ion are joined at the hip! If there is ever a need to prove that we are not far removed from gullible apes led by a cleverer ape, the continued abidance of men to those who wear funny robes is sufficient proof.
(When Bismark fought the church.)
(When Italy gave the Vatican Independence, and a stipend as part of a political compromise.)