Is a scan of the certificate of conformity sufficient for a registration request?

Yes. In France, scanning the certificate of conformity is sufficient to register a vehicle. You will receive it by email at the best price and within a short time.

SOURCE: https://www.legifrance.gouv.fr/loda/article_lc/LEGIARTI000049860443

Amended by Order of June 21, 2024 - art. 2: 

"Applications for registration of a new or used vehicle are sent to the Minister of the Interior either electronically or through an automotive professional authorized by the Minister of the Interior."

You must provide a digital copy (photo or scan) of the following documents: ( Art 1. E. 2) "The certificate of conformity to an EC or EU type may be a duplicate of the certificate issued by the manufacturer or his representative in the State of first or previous registration, or a copy of the certificate certified as correct by the authorities of the State of first or previous registration."