In France, if I plan to earn any money from a website I built, I need to create at least a "micro-entreprise" [1] to declare my income (up to 32,900€/y for a SaaS).
[1] https://www.service-public.fr/professionnels-entreprises/vos...
Edit: If you know French- https://fr.wikipedia.org/wiki/Entreprise_individuelle might be your answer.
The big diff apparently is that everyone in the US is sole proprietor by default, while in France you need to ask an agreement from the government.
- get a SIRET code [1] (id of your business, needed to make invoices)
- declare your income to pay your income tax and your social taxes
- be eligible to the national health insurance
- increment your rights for the social pension
- update the national statistics [2]
- be eligible to the ACCRE [3] (tax reduction during 1 year)
- be eligible to the ARCE [4] (a capital equals to 45% of your unemployment indemnities, from the social taxes you paid from your previous jobs)
And probably other things.
[1] https://en.wikipedia.org/wiki/SIRET_code
[2] https://en.wikipedia.org/wiki/Institut_national_de_la_statis...
[3] https://www.service-public.fr/particuliers/vosdroits/F11677
[4] https://www.service-public.fr/particuliers/vosdroits/F15252
Depending on what you are doing, you may also need a similiar tax id from your state (and possibly any other states you are doing business in, if you have a physical presence there). Most states have on online process similar to what the federal government has.
Then, you may need to register with your city and get a city business license- some cities don't require this for all types of businesses, but this can be one of the most expensive and difficult parts of the process, as you usually have to go to city hall and pay money for it.
But all of the above can be done as a sole proprietor. It is also fairly easy in many states to get an LLC setup online for not too much money if you want to go that route... though this depends wildly by state, I have heard California is a (comparative) nightmare to do this in!