Thansk for the replies. I was going to be travelling with someone who would not be able to sit in the emergency exit row, which is why I was considering the business class.

In the end, it turned out that I have to be in Paris the day before I fly to Copenhagen. Rather than comming all the way back to Madrid, I've booked two single flights with Norwegian, Paris > Copenhagen and Copenhagen > Madrid.

There were not any OW options from Paris that didn't involve a transfer.