My travel guide says that the use of foreign bank cards in shops in Denmark (restaurants, etc.) is frequently subject to a +2% or +3% “extra charge” for use of foreign card. But the guide is not pretty clear whether it's all card, only debit cards, or only credit cards. And how common it is in Copenhagen, and in what types of shops (small or big)?
Edit: my card is French, and my French guide book says that's considered “foreign” even though it's EU-issued.
Can anyone help explain this extra charge?