I think this is somewhat simplistic regardng Germany, though I do see why French National Collectivism would rather go ultramontanist/fundamentalist Catholic. I still think that some people flirting around with the Cult of the Supreme Being and/or Neo-Roman polytheism or Neo-Druidism remains plausible - Nazism in OTL also wasn't Neo-Paganist, but somewhere between secular and pseudo-Christian.Germany, due to late unification, was an archaic and patriarchal country. While France was centralized. Plus, the Catholic Church played the role of a unification factor before the Revolution, while Germany is still religiously divided.
I did indeed build on ultramonatanist fundamentalist Catholicism as a (but not the single) pillar of fascism ITTL - and later as an analogue to Islamism.