My friend - who is fiscally resident in Prague - opened a French bank account. Then, they used their French bank account to open an eToro (online broker) account. They want to invest on eToro but they don't know what taxes they will need to pay on her capital gains.
My gut feeling accompanied with some online searching is that she would just pay taxes in Prague, but I'm concerned about double taxation.
What taxes does a Czech Republic resident need to pay on investment income from eToro (an online broker) when using a French account?