Bonjour,
Participer à des Conventions artistiques ou scientifiques sous ESTA est une chose mais y vendre les produits de son art (ou de sa science) en est une autre
Si çà peut aider, deux exemples :
1. Convention d’art Anime Boston - The Northeast's Largest Anime Convention
en avril 2019extraits du site :
A Massachusetts DOR Tax ID is required for participation in both the Dealers' Room and the Artists' Alley and must be submitted every single year an exhibitor participates. There are absolutely no exceptions.
Obtaining a Tax ID for Non-US ResidentsIf you are a resident of any country other than the United
States, you may encounter numerous obstacles in fulfilling the requirements to obtain a Tax ID from the
Massachusetts Department of Revenue. In these situations the process can be much more complicated and take a longer period of time. Taking at least ten weeks to obtain the Tax ID is not uncommon.
Anime
Boston is not qualified to give advice for anyone's specific scenario. The most we can do is to point you in the right direction. The best option is to call via phone the
Massachusetts Department of Revenue and the Internal Revenue Service (IRS) directly and explain what you are trying to accomplish. You may explain that you are attempting to sell artwork at a one-time, 3-day long event in
Boston which requires you to submit an Employee Identification Number (EIN) or Individual Taxpayer Identification Number (ITIN). Both the EIN and ITIN require a Social Security number, which is not available to non-US citizens.
The link for obtaining a ITIN while abroad can be found
here.
Even if you obtain a DOR Tax ID, you will also be required to have all other necessary documentation including, but not limited to, a work permit. Work permits are issued by the
U.S. Citizenship and Immigration Services department, not by the IRS or DOR.
2. Cas proche récent entre
USA et
CANADA d’un citoyen Américain souhaitant vendre son art dans des Conventions au
Canada :
Tips for U.S. Artists Doing Business at Canadian Conventions...
As a resident of Western
New York state, it’s funny to think that my closest conventions are not in
Pennsylvania or
Massachusetts but directly north of me in
Canada. For me, it’s
Canfurence in
Ottawa and
Furnal Equinox in
Toronto......The trouble is that the internet has plenty of sites, blogs, and other dense jargon to dig through.
Rather than making it helpful, it makes the whole process of selling in
Canada seem quite daunting. I’m here to tell you that a phone call or two will save you the headache and confirm the correct path based on the characteristics of your business and convention plans.
Note: this blog post is anecdotal with references, links, and phone numbers that can help reduce the chaos of trying to sell outside of the country legally. This should serve as a reference but does not replace the law.
J'ai déjà fait moi même beaucoup de suppositions ! 
J'avoue être totalement perdu dans tout ça... pfff