An estimated 300,000 car registration documents remain stuck in processing by the new online carte grise system, it has been claimed.
The Conseil national des professionnels de l'automobile (CNPA) said that the website for applying and processing cartes grises documents has struggled to cope with demand since the process went online in November 2017.
The association said that each of the six 'virtual prefectures' processing cartes grises has a backlog of about 50,000 applications, BFMTV reported.
It highlighted a number of 'bugs' in the system: including displaying a 'service unavailable' page at key points in the registration process, or failures to take into account drivers who change their name, after marriage for example.
Legally, motorists are unable to drive without a valid carte grise, and dealers cannot deliver new vehicles as registration documents have not been processed.
The Ministry of the Interior would not confirm the CNPA's 300,000 figure, and said that "numerous corrective measures have been applied" to the system.
"Since November ... 2.7million registration certificates and more than 1million permits have been issued," a government spokesman told BFMTV.
Sign up to our free weekly e-newsletter
Subscribe to access all our online articles and receive our printed monthly newspaper The Connexion at your home. News analysis, features and practical help for English-speakers in France