Bitcoins are treated like candy: When you sell them, you have to pay 19% VAT on your income from the trade. Easy as that.
Not so easy, after holding them for a year the profit is tax free and i bet thats not the final word in that matter.
FOr a private person, yes. However, that means you BOUGHT them and did not CREATE them. As someone who has "mined" them, you are theoretically responsible for collecting VAT.
However, I suggest instead simply selling everything on Mt. Goxor another platform OUTSIDE THE EU, since considering that Mt. Gox is an intermediary in Japan and you are selling on and for Mt Gox, the whole VAT law is not applicable and you can then remark on its applicability when being asked.
Sell in Germany --> get fucked.
And again thats wrong, it depends on how often you sell something if you are a private person.
And whether or not you mined it. The act of mining is an act that will be translated as the miner having a "production facility" and therefore you will be paying.
THe only way to get around this would be marking with the "Small business regulation" or "Kleinunternehmerregelung" which allows small entrepreneurs to become completely VAT exempt to profits of maximum of 17.500 a year. At the same time, you can NOT choose this route if you are already a registered entrepreneur or have a company registered that is not a small entrepreneur.
If you BOUGHT bitcoins and then sold them, you are doing speculation as a private person and can claim full tax exemption on income tax.