For any english speaker coming around:
@Mandy38 has a debit card (matercard gold) from Crédit Agricole (France), and Revolut is taking fees when topping up.
In the in-app chat, Revolut support requested him to prove that his card is not commercial.
It has to be noted that I own a card with the same bank (mastercard debit, not gold) which has no fees. A relative has a mastercard credit (not gold), also no fees.
The easy conclusion here is that Mastercard Gold = Commercial card ? (from a Revolut point of view)
It is a bit disappointing and I can understand the frustration when people see everywhere the “no fee” advertising, and have to pay fees the first time they top-up with their regular debit card.