I've been over here in France for the last 20 years and here also now and then before that for another 10.
I've found that the French vastly over-value things. Especially cars.
However, after having said that the guy you are dealing with will never get anywhere near what he's asking for his car.
Make him a silly offer and if he says no then just walk away from it after giving him your phone number.
If that car went to a French garage with all those faults that French guy would have to take out a mortgage to pay for it with what French garages charge.----
I've done that silly offer thing with two houses I've purchased over here and in both cases got many thousands of pounds off the asking price.--
£11,000 in one case and £40,000 in the other.