Honestly , they continue to copy the laws in Italy. In that fair republic they have what is called the Guardia Di Finaza. It is essentially the money police. Every vendor is required to give you a receipt , even for the smallest purchase. If they do not , they get audited. It is not a pleasant experience. Very hard to do much in black , but the Italians have mastered the art.
Under the new austerity laws passed last year , it is illegal to keep more than 1000 Euros in your home. Any check or bank transfer over 1000 euros is flagged. They stop high end cars on the street and instantly check tax returns vs. values of the car. Think Ferrari.
Also , they walk the docks at marinas and clubs , run boat registration number vs, tax returns. How can you have a 200,000 euro boat and pay the marina if you only declared 50,000 euro in income ?
The reason they do not do it here is then the corrupt folks in government would have a harder time being corrupt.