What is it and when to act?
The first step is determining your legal status — it affects everything: taxes, insurance, registration and contributions. Do this before any other registration.
Freiberufler vs. Gewerbe
Freiberufler (§18 EStG): doctors, lawyers, architects, journalists, translators, many IT specialists, artists. No Gewerbeanmeldung, no Gewerbesteuer.
Gewerbetreibende (§15 EStG): retail, catering, manufacturing, agencies, online shops. Gewerbeanmeldung is compulsory.
I was convinced I was a Freiberufler as a web developer. The Finanzamt asked me to describe my work in more detail. I explained that I do software development and architecture — they confirmed Freiberufler status. How you describe your work is everything.
I opened an online shop and thought that was a liberal profession. It isn't. Retail is always Gewerbe. I had to do the Gewerbeanmeldung first and then submit the tax questionnaire to the Finanzamt.