Have been trying to determine whether a combination of 1 Pfizer + 1 Moderna vaccines is accepted in France as fully vaccinated. It is not clear in the various official websites and I'd like to be sure before leaving for France in January.
I found this article from September that seems to say that you should not have a difficulty.
https://www.schengenvisainfo.com/news/travel-to-eu-which-eu-countries-accept-mixed-covid-19-vaccine-doses/
My pharmacist here in France is mixing my booster shot. This doesn't answer your question, but it is done here.