The act of taking the photograph is probably not illegal.

But something to the tune of "All user biometrics shall only be stored with the consent of the subject." pretty much means it is illegal to do so, unless you have some sort of sign.

This type of law is usually under the guise of protection of personal information, or some other flag. Though the laws vary in many countries. For the sake of argument, I'm simply saying it's not illegal to photograph someone entering your property in order to point out how "secondary" or "related" laws apply without ever explicitly being defined so.

European data protection rules apply to CCTV systems; they're generally legal with signs and appropriate policy.

(Compare US law on taping phone conversations)

Without his consent? Absolutely. In Greece the police will have you remove any camera that faces the street (even a small chunk of it) if you're not a bank of course.

Now when we're talking about private property, written consent about what you do with that data is obligatory.

Indeed these banks receive tons of lawsuits every year, but if there's something more rotten in Greece than the economy is the justice estate...