Definitely something less [like the photo], as the pants create the texture/volume you would otherwise see up top. You can always go with a pattern, but the shirt itself should be simple. You could do a cute tank top or even a long sleeved shirt.
Thank you all ...yes I plan on wearing it with 5 inch heels. I think I will just stick with a nice tight fitted tank top. I was trying to stray away from that since to me its sort of plain looking and I don't care too much for accessories other than my real jewelry.
I wear harem pants all the time and pair it with an Alexander Wang T or something drapey and assymetrical from Pleasure Principle, Complex Geometries, or Rick Owens. I've got 3 pairs of harem pants and just love them.
I agree that they should be worn with heels. I think a simple but drapey/flowy tank top would work. A fitted top is fine too. I love pairing mine with a cropped and fitted blazer and a tee underneath. When it's cold I sometimes pair my harem pants with my SWORD Volterra fitted leather jacket and a skull scarf.
You can wear it as a dress too, which looks ridiculous on me. The pants are way more voluminous than the first pic posted here. They are by Pinkerton and come in another fantastic, bolder pattern as well.