Luxurious and light filled apartment with park views

A bright, light filled apartment in central Stockholm with luxurious details and a sophisticated style, spacious Boffi kitchen, intricate moulding and minimal Platner furniture is so beautiful. The windows apparently overlook a park in Karlaplan which is in Östermalm, Stockholm. I don’t mind the blank walls but what do you think about all that empty space? Would you fill them with art, add just a few choice pieces or leave the walls as is?