This sort of arrangement is common in Europe, or at least was so traditionally. It is indeed a practice sanctioned by the Magesterium. Indeed, historically, the United States was the exception, not the rule in not having church taxes (though some states in the early Republic levied taxes to support the established Protestant Churches). France, for example, levied a 10% income tax, the proceeds used to pay the salaries of the clergy before the Revolution.
As for the case of Germany, historically the secular government was in charge of maintaining the churches, It would be part of the state budget, just as, say, defense spending would. In the nineteenth century, eventually, German state governments (since 1871 with the exception of Communist East Germany, Germany has been a federal state, even if the Nazis subverted its federal nature in practice) transferred the responsibility of upkeep of churches and paying clergymen to the Church itself; however, the state government continued to collect the funds on behalf of the Church, which they then paid in a lump sum. In fact this practice is guarranteed in the German Basic Law (de facto the Constitution).
Of course, the problem lies in the fact that the tax in Germany is rather high - 9% of their income tax bill (except Bavaria and Baden-Wuerttemberg, which has it as 8% of the income tax). Italy, by contrast, has the rate at 0.8% of their income tax bill.
Note that this is 9% of your income tax bill, not 9% of your income. So, for example, Gerd has an annual income of €50,000. His income tax rate is 20%, so his income tax is €10,000. Gerd is Catholic and lives in the state of North Rhine-Westphalia, so the 9% church tax is applied to him. That means that 9% of that €10,000, that is, €900, will go to Church. That €900 (about $1,100 at present exchange rates) amounts to 1.8% of his income.
Honestly, the bishops are right on this one. Are you really willing to apostatize from the Church for the sake of a thousand bucks? If you are, that says something about you.
