A few large artwork over tje sofa would be sufficient.

Dytecture is right, you do not need to add a shelf over the sofa. You could do a gallery wall of black and white photos or just one large scale painted canvas. If you are looking to add lighting to the room you could flank the gallery wall or artwork with a pair of wall scones. If you do decide on hanging scones, make sure that your art is not covered with glass as the lighting would produce a glare and obstruct the pictures.

Thank you for your helpful comments.