주식인지, 뮤추얼 펀드인지, 결혼했는지 등에 따라 다릅니다. 아래 참고하세요.

https://taxsummaries.pwc.com/germany/individual/income-determination#:~:text=Capital%20gains%20from%20financial%20investments,Related%20expenses%20cannot%20be%20deducted.

Capital gains from financial investments (e.g. sale of shares) are subject to a flat tax rate of 25% plus 5.5% solidarity surcharge (in total 26.375%, plus church tax if applicable), which is basically withheld at source. Related expenses cannot be deducted. Capital gains qualify for the 'investor's allowance' of EUR 801 (EUR 1,000 as of assessment period 2023) per taxpayer and year for the total of all financial investment income. This amount is doubled in the case of married taxpayers filing jointly. Special rules apply on the taxation of capital gains from the sale of a significant interest in a corporation (1% or more).

Special partial tax exemptions apply on capital gains from the sale of mutual funds units, depending on the nature of the fund.

Other capital gains are taxable in Germany at individual progressive rates only if the sale is within one year (for movable assets) or ten years (for real property) after the purchase date. These capital gains are only taxable if the profit exceeds EUR 600 per year in total. Further tax relief may be applicable under specific conditions if the property was used for private purposes.

결혼했고 주식만 합니다. 저기있는 정보로는 부족해서요.. 800이하일때도 무조건 신고해야하는 건가요??

신고 해야죠. 신고를 해도 800유로 까지는 세금을 물리지 않습니다. (이제는 1000유로로 바뀌었죠.)