What typically works for your situation are a few things: you can hang a nice sconce on each side, or break up space with a tall bookcase or even a floor lamp. If you have side tables next to that sofa, you can place a couple of tall table lamps on them, or a nice pot with tall flowers or a plant to somewhat fill that space. Remember, open space is often good, it gives the eyes a rest, and it doesn’t have to be the exact same thing on each side (unless it’s sconces, of course, as they should match). My favorite option is sconces if you’re able to do that. I hope that I’ve answered it with a solution for you.