I am a resident of Germany. Should I buy stocks on the Nasdaq or the German electronic exchange Xetra from a tax point of view?
The tax treatment of a given security will depend on your specific situation so would be difficult to answer here.
However, the German listings of the security are to cater for the local market, so you may find preparing your taxes a little easier in that you do not need to factor in the prevailing exchange rate at the time of your trades. A German broker may be more easily able to provide any documentation you need, and if you have any problems you can go to a local regulatory body.