Disclaimer: I am not a tax advisor or tax lawyer. All information provided here is my best knowledge but I can not be held accountable for it. Please talk to your tax lawyer for more information!
The short answer is: Yes! All rewards you receive from delegating/staking your ADA is a taxable event as soon as it exceeds €256.-/year exemption limit. Tax obligations occur the moment you receive the ADA to the corresponding price of ADA in €. So for example:
01.01.21: 150 ADA at a price of €1.00 each
06.01.21: 200 ADA at a price of €1.20 each
In the case above you have a taxable amount on €390.-
Staking rewards are taxed as a part of your progressive income tax. In theory this can be up to 45%.
No. The tax event happens as soon as you receive the rewards, no matter if you sell them or not. Selling the rewards at a later point is not taxable though. In case the price of ADA rises significantly you can cash out the speculation gains for free. In case the price of ADA decreases you still get taxed on the price at the point you received those ADA. It's your personal risk!
Instead of tracking your rewards manually you can use a tool provided by Adapools.org to calculate them by just providing a receive address of your wallet:
The most controversial discussion in the german crypto community is about the question whether the ADA you use for staking (not the rewards) can still be sold tax free after one year. In Germany private purchasing and selling of crypto is free of tax after one year of holding those coins. By participating in staking this so called "Haltefrist" is in question.
Upon my request to the tax authorities in Munich I was told that the Haltefrist gets extended to 10 years by participating in staking - which would make it extremely uninteresting to stake as a german citizen. However most tax lawyers proficient with crypto law doubt this and assume that the 1 year period is still valid. A very interesting video on this by Bitcoin2GO can be found on the link below:
We are currently in the process of declaration of our staking rewards with the local tax authorities and will report back once we have a clearer view!