Thanks for the reply Bev, I have heard of this and it's the reason I'm posing the question.They have started a program here to evaluate your French pension when you reach age 57 or 58. And they do ask you to provide information about other pension programs you have been part of during the years when you weren't working in France.
Don't know if they'll move up their evaluation, but you could contact the agency that has your French pension and ask.
A friend of mine has been told he can take retirement at 60 on a full French pension using his UK entitlement, which would mean 6 years earlier than in the UK. Can this be true? There surely must be someone out there who has first hand knowledge of what goes on.