All nationals of EU/EFTA Member States – though still with the exception of Romanians and Bulgarians - have the right to live and work in Switzerland. This means that they can also be self-employed.
Nationals of third-party states – countries that are neither EU nor EFTA members – who wish to work in a self-employed capacity in Switzerland must meet the requirements of the Swiss labour market.
Canton of Valais - Obtaining a work permit
Swiss Confederation - Setting up a business as a foreign national