I'm busy filling out forms to get insurance and they require that I specify into which category I would fall into.
The options are:
How would I determine this?
Currently, I work for a company in London, as a software developer. I am employed as a contractor and will work remotely when living in Germany.
Based on what I read on the subject (I have no first-hand experience with this), Freiberuf is one type of Selbständigkeit, the other being Gewerbe. Being a Freiberufler involves less bureaucracy and has some tax advantages but it's not allowed for all professions. In both cases, you must however register yourself with the Finanzamt and once you have done that, you would know in which category you fall.
Unfortunately, the law isn't completely explicit on what can or cannot be considered a Freiberuf. Basically, it should not be a regulated profession, and it must require special skills and be a scientific, artistic or teaching service activity. Beyond that, people obviously prefer to be classified as Freiberufler but the authorities occasionally refuse to grant them the status and it can end up in court.
Researching this answer, I came across a post about a recent court case precluding a software developer from registering himself as Freiberufler, although I was under the impression that many people did in fact do just that. So it seems a bit of a sensitive issue at the moment and it might be necessary to seek professional advice if you want to be absolutely sure about all the required formalities.
If you didn't register as Freiberufler or Selbständige at Finanzamt, you are none. Legally you are Schwarzarbeiter (illegal worker), at least as far as Germany is concerned. For both of them, you will need a work visa that allows you to work independently while being in Germany, and you need to inform tax authorities that you intend to work as a Freiberufler. Then, tax authorities will send you your tax number, VAT number, and from then on you would be reqquired to comply with the German law regarding doing your business. In any case, you will need to figure out how to do your taxes, retirement insurance, health insurance and so on.
There's no such thing as "I'll work for my company in England for a few months while being located in Germany". Of course you can do it without all of the above, but then you are basically breaking the law.
If you don't know how to do it, your best bet is to just talk with a German tax advisor that could help you filling out all the forms and registering as either Freiberufler or Selbständig. Many cities in Germany also offer free of charge consulting (in German, but some of the consultants may speak English) for people wanting to be self-employed. Similar support you can get from German Chamber of Commerce in some cities.
