Hard to say, there are hundreds of named white double peonies and probably even more unnamed ones. You'd need to do some investigating to tell for sure--bloom time, foliage, mature height and width, does it have side buds....It's very pretty, regardless.

In bloom now and about 30 inches . First year after dividing and moving to this site, so might not be at mature height. Only 2 blooms, but hightly fragrant. No side buds. A touch of maroon where leaves come off stem.