Let's imagine that the Concordat of Balogna, which gave the King of France complete control over church titles, never happens and instead Francis I seperates from the Vatican entirely a la England and Sweden. Then, let's assume, over time the church differs more and more from Catholic tradition in favor of Calvinism so that by 1600 France is a fully Protestant nation. What impact does this have w.r.t.:
30 Years War?
Development of Constitutional Government?
Revolution?
Colonies?
Economic Development?
Item: The Spanish will have more trouble holding onto any part of the Netherlands or keeping that part Catholic. France and the Netherlands may become natural allies.
Item: There will be a lot more intermarriage between the French royal house and the English royal house - and unlike OTL, descendants of these marriages will be eligible for the succession.
Item: the Auld Alliance between France and Scotland will be reinforced by common religion.
Item: barring butterflies, Mary of Scotland will be a Protestant. (She'll convert when she marries into France.)
Item: France's alliance with Poland may never develop.
Item: France will probably support the Protestant side in Germany earlier and stronger. If there is a "Thirty Years War", France will be deep in it from the start.