Actually, there are protestants in France. Littke-known fact, the official religions of Alsace-Misel in France are Judaism, Roman Catholicism, Lutheranism, and Calvinism.
From Wikipedia:
France: The local law in Alsace-Moselle accords official status to four religions in this specific region of France: Judaism, Roman Catholicism, Lutheranism and Calvinism. The law is a remnant of the Napoleonic Concordat of 1801, which was abrogated in the rest of France by the law of 1905 on the separation of church and state. However, at the time, Alsace-Moselle had been annexed by Germany. The Concordat therefore remained in force in these areas, and it was not abrogated when France regained control of the region in 1918. The Concordat recognises four religious traditions in Alsace-Moselle: the Jewish religion and three branches of Christianity: Catholic, Lutheran and Reformed. Therefore, the separation of church and state, part of the French concept of Laïcité, does not apply in this region.
https://en.m.wikipedia.org/wiki/State_religion