Good grief .. that can't be right. If you are talking about energy level use of the property.
From 2023 this happens ..
"C'est désormais officiel, l'obligation de réaliser un audit énergétique lors de la vente d'une maison classée F ou G, communément appelée passoire énergétique, est à nouveau reportée du 1er septembre 2022 au 1er avril 2023 d'après un décret publié ce jeudi."

Which is why, in my view, many old houses (mostly previously rented out) are being sold off now as from 2025 they will need to be better insulated to be able to be rented out. Soon the rent will not be allowed to be increased if the property falls into one of the 'high energy use' categories.

It's all about owners of properties which are rented out having to improve the energy rating of their housing stock.

If they have been classed F or G then surely they have already had the audit as part of the diangnostique which awarded the classification?

Mine was rating G and the heat losses were precisely calculated for each surface, precisely wrong because the muppet did not even know the difference between a mur en brique creuse and one en parpaing nonetheless it gave quotes for the various reworks and the energy savings they would create, equally fictional and many of them calculated out to a break even of 40 years, if you substituted real world figures then much longer.

I'm struggling to imagine any audit more detailed and involved than the one already produced albeit generated by a software package and mostly fictional.

I think houses which are classified F or G will be banned from being let, not sold. But it's true what pcpa says. The diagnostic tests are carried out by muppets with software and no common sense. I had a DPE diagnostic done a few weeks ago. It said that the ability to control the climate in the house during summer months was very bad and that the solution was to have volets fitted. I have volets on every window and door except the two toilettes, which have really tiny windows. So when I challenged the diagnostiqueur with the fact that 99% of the house was fitted with volets, he just said that's what the software says. Pathetic.

the official line
www.ecologie.gouv.fr/projet-loi-energie-climat-lassemblee-nationale-adopte-bloc-mesures-en-finir-passoires-thermiques
There is an interesting section on exemptions

The need for an 'energy audit' actually comes in next year for houses that have a poor energy rating (F or below).

Whilst I back the cause the current methodology around the rating is flawed, when we bought our current house it had an 'E' rating due to it having single glazing and no insulation, we spent 30K on double glazing and mass insulation but when we had the diagnostics done in April the rating had fallen to an 'F'!