I am planning to carry less then 200 grams of gold with me in a flight from Turkey to Madrid. I wonder if this is okay and if I have to pay some taxes.
Bringing 10000 EUR in cash or equivalent -- which gold is -- requires a declaration. It's all fine and there's no VAT on gold but you need to declare. You might be even below that: today a gram is 44.45 EUR which means 200g is a bit below 9000 EUR. So: you should be fine. If gold surges between now and when you enter the EU you will need to declare.