Vid närmare eftertanke så ska Amex privat också vara undantaget
Charges for using your card
When you
pay for something in the EU using your credit or debit card, traders and banks
cannot charge you an extra fee – also known as "surcharging" – just for using a particular card. This rule applies to all card purchases (in shops and online) made
within your home country or in another EU country.
Warning
Credit and debit cards issued by three party schemes (such as American Express and Diners Club), and business or corporate credit cards, where your employer is billed instead of you,
are not covered by EU rules on payment services, and you can still be charged extra for using these cards.
Payments, transfers and cheques in the EU - Your Europe