Greece is speeding ahead. Here the maximum amount for cash payments is 500 (!!) Euros. Everything above has to go through the banking system e.g. with card payments. Cars are currently exempt. It's planned to have a further reduction to 200 Euros max and to scrap the car exemption.

Source (in German):

https://www.evz.de/finanzen-versicherungen/bargeld-obergrenze-in-der-eu.html