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.
You are messing things up.
Say you buy Bitcoins for 10 Euros in December 2013 and sell them for 20 Euros in August 2013.
Then you pay 25% tax on your 10 Euros win (Abgeltungssteuer). If you are a professional, you pay an additionally 19% on the 20 Euros revenue from the selling. If you are a private trader, you pay just the 2.5. This is comparable to you selling your old stereo on ebay for private reasons. You are excluded from VAT there as well. If you do this 100 times a year (the threshold is actually lower), you are considered doing this professionally and your sells are subject to VAT.
If you buy Bitcoins for 10 Euros in December 2013 and sell them for 20 Euros in January 2015 you pay no tax on your 10 Euros win (held for 12 months+). If you are a professional Bitcoin vendor, you still pay 19% on the 20 Euro revenue from the sell.
We are talking about two independent taxes! Dont confuse others by mixing them up.