I just used the 20GB €40 Orange Holiday plan as an eSIM on my trip a couple weeks ago. It worked great while in London and on a side trip up to Bletchley Park. Also worked fine while in the Berlin and Krakow areas. My only experience with it in France was while on a Eurostar from Brussels (where it worked fine) to London. I'd assume since they're including a French phone number it'll work without problems in Paris.