> Visa transactions costs are 0,22 € out of a payment of 1 €, Mastercard's is 0,23 €, and the French CB network is 0,17 €.

Are you sure of these values? Because that's different from what I was told, which was that CB was cheaper for transactions of more than 10 €, because their fees were fixed, not rates like Visa and Mastercard.

From what I've just read (not counting the possible extra tax by the bank of the seller):

CB: 0.20% + 0.00117 € ⇒ 0.00317 € for 1 €, 0.20117 for 100 €

Visa: 0.20% + (0.01% to 0.014%) ⇒ up to 0.00214 € for 1 €, 0.214 € for 100 €

Mastercard: 0.20% + (0.15 to 0.17%)

The 0.20% is for the "interchange" described in the article. So it applies only when the seller and the buyer do not have the same bank. The maximal rate is fixed by the UE, and AFAIK everyone use the max value.

> Are you sure of these values?

Yes perfectly sure, just checked. I'm not saying these are visa fees vs CB fees. Lots of actors in the chain. But that's what I'm paying for each card type.