My DM and DSF have had a house in France since 1986 and they considered moving there full-time in retirement. However, after spending more and more time there over the years they have opted instead to live in England and just spend as much time in France each year as they like, with their French house purely as a holiday home. Why? There are two main reasons:
- French inheritance law (second marriage on both sides and they want their two estates to be distributed according to English rather than French law);
- Their family is here and so are all the friends they've had their whole lives and you simply cannot replace people like that, however nice new friends you make are. This led to my DM, in particular, finding life in France very lonely after the novelty of being there wore off.
If you're seriously considering this huge life change I would urge you, having lived OS myself, including in France, to apply yourself immediately not just to learning holiday French (Hello! Goodbye! Where's the bank? Two ice-creams please), but really learning the language. If you want to buy a house, do it up, connect the gas, get a phone line, understand your French bank statement, and make any friends, you will need to speak decent, conversational French. Just think about all the interactions you have every week in this country with service providers, friends and neighbours - you will need to be able to do all those things in French. Don't rely on them speaking English! For buying property you'll need a bilingual lawyer and that shouldn't be too hard to find, but all the other stuff you will need to be able to deal with on your own in French. In your 50s it will take some considerable effort on your part to learn a new language, so I would sign yourself up for an intensive course and see how you get on. The Institut Francais in London has excellent intensive French courses. I took one myself and made really fast progress www.institut-francais.org.uk/french-courses/
TBH, if I was you, I'd arrange to spend a few months (three-six, say), in a rented house in the area you're interested in and give it a try before you commit yourselves to selling your home here and moving lock, stock and barrel.