[ernesth]

>> In France for instance if you accept credit cards, it is illegal to add a fee for accepting it.

> Are you sure, that it is by law?

It is: Article L112-12 from the Code monétaire et financier. "Le bénéficiaire ne peut appliquer de frais pour l'utilisation d'un instrument de paiement donné." (The seller shouldn't charge any fee for the use of a given payment instrument).

https://www.legifrance.gouv.fr/affichCodeArticle.do;jsession...

More generally, the law requires that the total to pay is to be presented to the client before he choses how to pay.

[vetinari]

Interesting, thanks.