I live in Germany.
If my father would want to give me a large sum of money - let's say 10,000€ - what would be the safest, least bureaucratic way to do this? I'm an apprentice and I still receive child allowance (I don't know how familiar people outside of Germany are with this), and I have no debts.

What I am afraid of:

* Missing out on the best way to store such an amount of money for a large time

* Losing money to bureaucracy (German authorities)

* Losing money on the transaction due to some taxes (I have no idea about this)

Another thing I'm afraid of is that my girlfriend, with who I am living with and will be living for a long time, has a mother who has a lot of debt. 

I am NOT concerned about interpersonal issues (her or her mother wanting money), I am ONLY concerned about legal troubles i might have if a person I live with has a relative with a lot of debt, but that is not my main worry here (as even I with my limited knowledge can tell that the risk for me wouldn't be big as I'm not engaged to her).

Also, my ideal future scenario would be to use this money to finance a flat in another town, so that someday I can own said flat myself instead of living on rent forever, but I know that 10,000€ would not be enough for that - maybe there's something where you can start small?

Sorry if the text body goes a little out of scope, I'm just a little anxious about all of this, and I wouldn't want to start anything before at least getting some feedback here.

Thanks in advance!