You may find it hard to believe, but that's the way it works. It is not progressive (as I have verified many times against my paycheque!).

The tables are straight-forward: take your gross pay, find the corresponding tax rate in the table, and your entire pay is taxed at that rate. For the vast majority of people (earning 240k or less a year), this works out fine, because for up to 20k a month, the tax is incremented in bands of 50 francs, so the situation described above (where lower gross pay = higher taxes) doesn't happen. The problem is that above 20k, there are only three bands (20-25k, 25-30k, and 30k-1000k).

For me, the big drawback of the quellensteuer system is that it assumes your pay remains the same every month. So if you receive 30k one month, your tax is calculated as if you earn 360k a year. It penalises people who receive differing amounts of pay each month. Every ex-pat who only pays quellensteuer will complain about the tax hit they take when they receive their 13th month, their bonus, or their relocation allowance.

At least if you file a tax return, you pay the appropriate amount in the long run (never mind that the tax man has your money until then...).