I've seen a lot of clawfoot tubs with subway tile accent wall(s). Some clawfoot tubs are painted black. Maybe the grey tile floor, white subway tile, black outside the tub? too much tile? too much white?
I love the white subway tile with the white grout. HOUSE TOUR: Coldplay's Jonny Buckland at Home - The tub, fittings, and tiles in the master bath are all by Waterworks, and the vintage light fixture is from JF Chen.