Don't think there will actually be a Fantini distributor in France, as I've never seen any adverts for them over the years.
How it used to work in the UK was that some dealers would undertake to order a box for you from a maker they ordinarily never dealt with. The dealer could not speak Italian, but would nevertheless ask you how many diamantes you wanted on it, what precise colour you would like, your name on the front etc., etc., etc. After all they wanted to maximise their profit on a one off deal. You then paid a deposit and waited, and waited, and waited....... Normal waiting time from order to delivery varied, but you'd often be told it could be a few months.
Maybe three months later you would chase it up to be told that there was a "problem" somewhere, but if you were lucky it would eventually arrive, weeks or months after the date you had been promised. You then went to pick it up to discover that it wasn't actually what you had ordered, but the dealer was still looking for the cash to finalise the deal. You never had a chance to play it until it materialised, and even if you had managed to have a go on one before placing the order, the one in the dealer's shop wasn't exactly the same, particularly if it had musette tuning.
If you were lucky, and I really mean this, the maker would decline to supply the dealer unless they ordered, and paid for, a demo range of that maker's instruments, with a view to the dealer becoming a distributor. In those circumstances it was a straightforward "no deal". You never got ripped off and the dealer never had the hassle of trying to tell the maker they'd got something wrong, in a foreign language.
What I'm trying to say to anybody contemplating a new instrument, if there are no official distributors near to where you live, you may be as well to consider another make and/or model of box. If you are a professional player of some standing (sorry dreaming again!) the maker might recognise you and make a special effort to comply with your wishes, but if it is a more or less standard production model, and your name doesn't register in the all time greats, you just have to end up taking what you get.
The one and only time I tried this I was still waiting for the accordion I ordered over a year later, and as communication between myself and the dealer became difficult, I ultimately cancelled the order, losing my deposit. As I lived in Scotland and the transaction was handled under English Law it wasn't viable to try and sue for my money back. Although I'll never know what actually happened, it appears to have been the case that the dealer had made an error with the bass configuration, and Piermaria naturally refused to alter it without recompense. The fact that my order had been a one off "special" for export was probably a factor, and the dealer concerned is now deceased. My experience may have been unique to my particular order, but I've heard other tales of woe from the days when such transactions were carried out on a regular basis (when the accordion was more popular than it is now).
If I can think of any positive experiences on this topic, I'll be sure to post it.
In the meantime "caveat emptor", as they say.