The goal of the Enlightenment was to free the individual from oppression by the church and state. Therefore, it should come as no surprise that the French Revolution, which was fueled by Enlightenment ideals, tried to remove the Catholic Church from France and replace it with a state-sponsored form of deism.
Pre-Revolutionary France was made up of what was called the Three Estates: the clergy, the aristocracy and the regular populace. The Third Estate made up 98 percent of France's population and paid all the taxes, yet had no voice in government aside from the Convocation of the Estates-General, in which they could be -- and were -- outvoted by the representatives of the First and Second Estates, who had the same number of votes as the Third Estate and an interest in maintaining the status quo. The Catholic clergy, therefore, was strongly associated with the aristocracy and oppression of the people. This would not help their case in the coming revolution.
Clergy and the Civil Constitution
To placate the people, Louis XVI decided to take the 6 percent of land owned by the Catholic Church in France and grant it to the National Assembly. Meanwhile, the National Assembly created a Civil Constitution of France and, in 1790, passed a decree saying members of the clergy had to swear an oath of fealty to the constitution or leave France. Only seven clerics in all of France did so. Thus the First Estate was summarily eliminated from the country of France and its property was seized. The Declaration of the Rights of Man also granted equal rights to those of other religions, including Judaism.
The Cult of the Supreme Being
In 1793, Maximilien Robespierre took charge of the new Committee of Public Safety, which became the de facto French government and ushered in the Reign of Terror. The goal of the Committee of Public Safety was to completely transform French society, going so far as to create a new calendar. Some committee members were atheists, but Robespierre proposed -- and actually set in place -- a state religion called the Cult of the Supreme Being, which was based on Enlightenment deism. He even instituted a "Festival of the Supreme Being" in the summer of 1794. Shortly afterward, he was guillotined.
Napoleon and Concordat
Napoleon was not fond of Catholicism, but after taking charge of France he decided it was important -- both to himself, politically, and to the stability of France -- that the Catholic Church return. One of his first acts as consul was the Concordat of July 1801, which removed the anti-clerical laws of the revolution while keeping Catholicism the religion of "the majority of the French people," rather than the state religion. Once stability was reached, however, Napoleon took every opportunity to subvert the pope's authority in France, and the church never reclaimed the authority it had under the Capetian monarchy.