So, I was wondering about an ATL in which France became the dominant power in the 18-19th, maybe even 20th century.
However, I am not thinking that the PODs should occur during the Napoleon Wars rather than during the late medieval ages and early renaissance. I thought about two major factor which, once achieved, could turn the tables in many a wars to come, and other things as well:
Somehow, France would have to incorporate all of Burgundies possesions into its territory, and then turning protestant.
My main concern here is that the Netherlands do not go to Spain but completely to France, possibly even while they become protestant. Through the second major event, France would have to decide that the Pope's power is too strong in comparison to their King's one. Thus, the King decides to embrace his dutch subject's faith!
This would probably lead to France being less centralised, more independent from catholic faith and probably also with a great base against both England in naval issues and one of the strongest economic regions, especially during the 17-19th century (but also beyond). Protestant faith would secure a more unified state, and together with the more decentralised nature of the ATL France the Dutch could stay integrated into the French Kingdom.
This could also lead to a little Britain in France, in a way that they create a constitutional monarchy instead of the absolutist which in the end was one major reason for the French's ferocity during the revolution.
So - would this be enterily unprobable or somehow managable to achieve? I do not expect it to be near to our timeline, only to be at least partly plausible.