This obviously creates a paradox, as you can't pay taxes on revenue generated by "nothing". I don't know which European country you're from, but I'm Norwegian.
Our tax authorities didn't recognize BTC as being VAT (value added tax) exempt until
about three years ago. For the time being you're in a legal limbo, and at the bare minimum I would advice you to report any BTC holdings on your tax returns.
However, I wouldn't start paying taxes on an unrealized gain (although I don't know what your intention is with the investment)..As soon as you exchange that money into fiat currency, the snowball starts moving though.
Best of luck regardless.
Virtually every country tax laws will want you to disclose all your income and pay tax on it but the same tax law will state what qualifies as income that would be taxed or otherwise. For example, income from loss of office or pension payment is exempted from tax which means you can derive income from such sources but tax will not arise an that does not mean its nothing.
In the case of bitcoin over here, the law has not been expressly stated which means that we are enjoying tax free income and I don't see that changing any time soon but there are discussions on how to ensure that this is captured but the concern is the moment they are looking at income from that end, then they are talking about legalizing it as well.
