Moving this over to the France section, as it seems that's the country you're interested in.
Possible typo - do you perhaps mean "brocante"? Or else I've just stumbled onto yet another unfamiliar word in the French language. (Happens all the time...)
Unless you're starting out under the auto-entrepreneur statute, you'd most likely be making your cotisation payments to the RSI. They simplified things a year or two ago and instead of all the various caisses, there is now one unified caisse for artisans and "commercants" and that's the RSI.
If you set up your business as a separate entity (i.e. an EURL or SARL or something similar) cotisations run about 38% of your base (your declared professional revenues including any optional cotisations paid for by your business on your behalf) plus 8% of the base plus any obligatory cotisations that your business pays on your behalf (like retirement funds, mutuelle and/or prévoyance).
If you're a gérant minoritaire, you pay the regular cotisations like any salaried employee.
Cheers,
Bev