I imported one back in 2015 so some of the paperwork requirements could be different now, thanks to Brexit, but as far as it being standard goes not difficult.
There is a site that you send off to for a 'attestation pour l'obtention d'une carte grise "Vehicule de collection" or for a "normal" registration, this would be done by the purchaser once the car is here.
Basically if the model of car was sold in France then it will be listed and straight forward. The engine needs to of the same capacity as when first sold. Different exhaust system shouldn't be a problem, as for wire wheels they'll be fine - mine arrived with Minilites and I still got it passed under the stricter rules of "Vehicule de collection".
If you want to look at the FFVE site
https://www.ffve.org/obtenir-une-attestation-ffve
The buyer has all that to deal with as well as VAT declaration/exemption, CT (MOT).