Yes and maybe, and no
the seller can go on-line to get "certficat de non-gage" - a notice that it is not assigned to a loan or debt. The "controle technique" must be less than 6 months old. Once you have agreed on the price and bought it. You will need to cross out the "carte gris" and fill out "certificat de cession" (see here
http://www.interieur.gouv.fr/sections/a_vo...=1152631071.98). All this can be done away from France - you will then need to address within 15 days the "cession" to a prefecture (you will need to have an address in France for this).
You must insure the car as of the moment of sale, it is illegal to drive without an insurance and could cost you a night in jail, if caught. You can have your car insured with French plates here, but you will need an address in France. And then you can only legally drive it here for six months.