>Only it’s very weird to just assume that this might apply to bank deposits…

Is it? I find it weird you think so. If you and I exchange > 3000 between us, nobody will ever know, so the law is pointless. The one place that this can be policed is at the bank level. You're assumption seems to be that if you gave me 3000, I'd just keep it in cash.

In the US, if you make a deposit > $10,000, the bank is regulated to report it. It doesn't matter why you are making that deposit, it gets reported. Applying the same thing to Euro markets only seems natural.

Edit: Actually, even car dealerships have to report someone showing up to buy a car with >$10,000 in cash as well.