MG,
First of all, this is not a subject I know a huge amount about. I've visited France a couple of times, been made very welcome every time, but only once ventured to an uncontrolled field. So my comments are based more on what I've read than on any real-life experience.
Having said that, a few thoughts spring to mind:
1) There are plenty of fields in the UK, some of them quite busy (White Waltham is one which immediately springs to mind), where non-radio aircraft are frequent visitors, and this kind of problem does not occur at these fields. So if it is possible to fly the correct circuit when non-radio, surely it can't be any more difficult to fly the correct circuit when the r/t is in a foreign language?
2) There are many guides on the internet with a list of English aviation terms and their French equivalents. So the absolute minimum r/t which should be possible, even without knowing a word of French, should be to download such a guide, and read from it when in the circuit. Even if you're not able to understand the French r/t (I speak a tiny bit of French and a tiny bit of German, and I can usually make myself understood, but understanding the natives is a different matter entirely, so I can quite appreciate how it might be difficult for an Englishman to understand French r/t), making calls in French will enable others in the circuit to hear what your intentions are.
3) I don't have it in front of me, but I believe the Jeppesen Botlang guide to France quite clearly states the language or languages used at each airfield, and for the vast majority (maybe even all) of uncontrolled airfields, the only language listed is French. So saying that "English is the international language of aviation" is wrong, and not acceptable at all.
I would hope that language barriers would not put people off visiting these fields, and would be against any measures which would cause people to be put off, because I believe that with appropriate planning it's possible to visit uncontrolled fields in France safely - but I am 100% behind any drive to get people to communicate in such a way that they can aviate as safely as possible - good luck.
FFF
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