France, my employer reports how much they pay me to the state. I tell the state how much I made, in a pre-filled form of everything they know. That includes sal

France, my employer reports how much they pay me to the state. I tell the state how much I made, in a pre-filled form of everything they know. That includes salaries, donations, as well as the default 10% tax write-off. I can of course adjust this form. I can also tell the state how much I expect to make this year, and the state will tell my employer to directly deposit a specific percentage of my salary directly for taxes to the state. When doing my tax declaration, if anything has changed, it gets all settled in September. If I didn't pay enough yet, I'll be asked to finish paying it (ex: this year, where my estimation of what I'd make was too low, and I'll owe 1000€ by September). If I paid too much, I'll be reimbursed (or it'll be paid in advance for next year.) All in all, revenue tax takes about 5 minutes a year for me to check that what they have is correct (since I am salaried, which is the easy path), and maybe 5 more minutes to adjust my monthly tax rate.