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... extraordinary income included therein
Specify the extraordinary income according to sections 34 and 34 b Income Tax Act (EStG). This must be income which is not subject to German income tax.
Extraordinary income includes in particular:
Remuneration for activities lasting several years
Capital gains
Compensations within the meaning of sect. 24 No. 1 Income Tax Act (EStG)
Extraordinary income must be taken into account when determining the tax rate, (so-called "German progression clause (Progressionsvorbehalt)"). This means that the income is included at the rate of one-fifth when determining your tax rate but not when determining your taxable income.
The conversion of income in foreign currency must be done on a monthly basis using the European Central Bank's euro reference rate. However, it is not objectionable if wage payments received in a foreign currency are converted on the basis of an annual conversion rate - determined from the monthly published VAT reference rates, rounded down to the nearest 50 cents. (Ministry of Finance (BMF) letter dated Dec. 14, 2014)