The Code du Travail (French Employment Code) is unequivocal:
Any contract by which a person secures the services of a model for remuneration shall be presumed to be a contract of employment.
DGT Circular No. 2012-06 of 26 July 2012 is also clear on this point:
The auto-entrepreneur scheme is applicable only to self-employed workers benefiting from the micro-enterprise tax scheme and covered by the social security schemes for self-employed workers.
It is not open to activities whose exercise implies a connection to the general social security scheme, which is the case for models: article L. 311-3, paragraph 15, of the code de la sécurité sociale (French Social Security Code) makes it compulsory for models covered by the provisions of Articles L. 7123-2 to L. 7123-4 and L. 7123-6 of the code du travail (French Employment Code) to be covered by the general social security scheme.
Consequently, models are not eligible for the auto-entrepreneur scheme.
The customer (and its potential customer, the advertiser) who employs a model as a self-employed person, would be in a situation of undeclared work:
"The offence of undeclared work is the intentional concealment of all or part of a salaried job (absence of a declaration prior to hiring, absence of a pay slip, etc.).
This offence also includes false statuses such as false self-employed persons.
It is also deemed to be undeclared work by concealment of salaried employment when the employer intentionally evades declarations relating to salaries or social contributions based on them to the bodies responsible for collecting social contributions or to the tax authorities by virtue of the legal provisions."
If the self-employed status is reclassified as an employee, the employer risks a prison sentence of up to three years and a fine of €45,000. Not to mention the image damage and the criminal consequences in the event of an accident at the place of performance, as the model is not declared.