In Finland, the withholding tax on dividends is normally 30%. According to the DTA between Finland and Germany, a maximum withholding tax of 15% can be credited on dividends.
@Texasman and @MarcoInvestment In principle, the withholding tax is 30%. However, according to the double taxation agreement, a maximum of 15% can be reclaimed via a corresponding refund form (some brokers also forward the data directly to the foreign tax authority, in which case only 15% is paid directly).