Gabriele Hi 👋,
If you refer to the IIN details of the MasterCard Credit Card, which is a specific number identifying the card issuing country, you will get the INN number based on the country you registered your bunq account with regardless of your local currency or local IBAN sub accounts.
At this link you can see the different INNs assigned per country from MasterCard:
https://www.creditcardvalidator.org/mastercard-issued
Regards
GG