It's called the ACCRE. It's for everyone who is applying via the pole emploi. It must be applied for within 45 days of starting your auto entreprise. Other people can benefit from the scheme as well such as young people and those recieving the RSA.
For service based auto entreprises it's 5,4 percent the first year, 10,7 percent the second year, 16 percent the third year. For selling of goods it differs, 3 percent first year, 6 percent second year, 9 percent third year.
If you want to apply for it, it's easy, one form called the Cerfa 13584 02 or is available on the service publique website: http://vosdroits.service-public.fr/pme/R17122.xhtml.
Jenn from Mon Ami Andy