More so, in Germany your taxes are deducted and paid by your employer in first place and he can't calculate the income taxes properly since he is usually not allowed to know too much about your life off work. Thus, your employer here usually deducts too many taxes from your income. And it is your duty to get the difference back - if you want so.
I already managed to nearly double my income in a year. A few months of paid work so the income stayed below the minimum threshold. Many kilometers of travel to my workplace. Additional expenses that had been deductable, because I moved into a new apartment. In the end, I got negative taxes - I got far more back than I have paid.