You will have to apply to the DREAL for a titre isolé, the equivalent of a UK SVA.http://www.direct.gov.uk/en/Motoring/BuyingAndSellingAVehicle/ImportingAndExportingAVehicle/DG_4022106
This will give you some idea of the scale of the hurdles you are going to have to overcome, to which you can add how you actually get on at the DREAL may hinge on nothing more than if the inspector likes the colour of your shirt. A pretty girl with big boobs and a low cut blouse could be your best ally - unless he's gay !
The problem with commercial vehicles is that for the most part they do not have a pan European C of C as each countries rules are different. A very simple example is in the way in which the relative weights and limits are calculated and stated on the vehicles plate. that will have to be recalculated to the French formula and a new plate attached.
On the other hand if they have inspected and passed an identical one previously it may
be a breeze.
All you can really do is apply and see where it takes you.
Here is the procedure.http://vosdroits.service-public.fr/F19222.xhtml
In English here
Bonne chance !