Tricky tax question, tax adviser/advisor needed (Prague)

Hello Everybody.
In May Protected content moving with my Czech girl friend from Germany to Prague.
First I do not intend to find a job for some time (yeah! ), but I have some “passive income”, that needs to be taxed by the Czech tax authorities and not by the German anymore I would
assume. Does anyone have that same situation (income from capital investments, a rented out house/flat or a business)? What’s my status then as neither being employed, nor self-employed?
I guess I would need to find a tax advisor that speaks either English, German or even Dutch to help me with my financial/tax move in order to not do any tax fraud.
I would be very grateful for any advice.