Where should I declare the tax if I am a non-resident individual?

Bank's Clients, non-resident natural persons fiscal in Romania, for determining any additional taxes and fees due for interest income earned from Romania, will be subject to the tax rules of the country of tax residence.

Banca Transilvania SA confirms that the withholding tax on interest was paid in RON to the state budget of Romania. To certify the interest tax paid in Romania, you can request at BT units Interest Income Statement which contains both the interests collected from the savings products at Banca Transilvania, as well as the tax paid to the State Budget.