I've used Jean Rousseau (in Paris) and was very happy with the work and the price for the service they provided (what does VFM mean?).
They are much cheaper now than Camille Fournet.
Also cheaper than Atelier du Bracelet Parisien /ABP, although ABP has great offerings and tons of leather choices on their website (at 160 euros for a web order).
The main advantage to me indeed is to be able to pick a very specific color and texture when there's no alternative on the market.
I also find it quite useful for vintage fixed lug watches as there is usually much less choice.
They were very accommodating when I asked them to use rivets which I provided for a military pilot watch.
The red lining below, which I really dig, was a standard option and not an extra charge.
Best regards,
S