A completely un-informed reply here from someone who's not (yet) in the industry, but here goes anyway:
I've seen several threads on here complaining about how it's harder for British pilots to get jobs since JAR has come about. Specifically, European legislation means that anyone from a European country can work in any other European country. And JAR makes it much easier for pilots from one country to fly in another. However, most airlines (quite rightly, IMHO) require their pilots to speak the language of the country in which the airline is based - and this provides a barrier for British pilots wanting to work elsewhere in Europe. On the other hand, just about every professional pilot across the world speaks English, since most ATC is in English - therefore it's relatively easy for European pilots to fly for British airlines, but not vice versa.
I don't know how justified these "complaints" are, but being able to speak French fluently enough to get by living in France for a year would certainly give you a big advantage in that you'd be able to apply to French airlines as well as British ones once you get your license, giving you a huge advantage over many of us.
I also can't see any logical reason why any airline would count that experience against you. And it sounds like a whole load of fun, and a great way of experience life in a whole new light.
I'd definitely say Go for it!
Good luck,
FFF
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