Turns out it is true.
https://europa.eu/youreurope/citizens/consumers/shopping/pri...
> Traders in the EU are not allowed to charge you extra for using your credit or debit card.
Regarding this:
> Nobody here is charging 2-3% except when credit cards are involved.
The service provider that provides the payment terminals merchants use will be charging the merchants between 1-2%, often with a per transaction fee on top of that. I’m not 100% sure how service providers in the EU bundle things, but intercharge fees are usually charged on top of that again. Even though the EU caps interchange fees, merchants will very easily be incurring above 2% in fees even for non-credit card transactions. The EU’s cap on interchange fees for card not present transactions is barely below standard market rates, so EU merchants will be paying about the same as everybody else for those.