Do you have a good idea for a business like Tarek and Max? And do you want to be your own boss? Then you'll have to complete a whole lot of formalities first. You'll have to go to several different agencies, and you need a number of permits in order to become your own boss here. But if your business concept is good, it's worth it. Depending on the type of business, you have to register with the trade office or the tax office. You may also have to fulfill some requirements, such as getting the master craftsman's certificate for certain trades.
Even if you're not German or an EU citizen, you can still start your own business or work on a freelance basis – provided that you are financially independent and your business idea promises to be successful. You have to demonstrate this with your Geschäftsplan (business plan) – this is the basis for a special visa. The plan is also necessary to apply for financial assistance, from a bank for example. But mainly it helps you to be clear about what you actually want, what you need to achieve it, and who your customers or clients could be.
Be sure that you take your time and get good advice. People who are self-employed in Germany pay value-added tax as well as income tax. There are also special fees you have to pay, such as for health insurance and social security. You can find information on the internet about how to start a company and where to get advice.