As I recall, DC was designed by George Washington himself (probably with help from his friends), back in the late 1700s, but the city as a whole was not: what they designed was the Federal district only. The Capitol, the White House, the National Mall between them, etc. Over time, this grew with the additions of the Smithsonian buildings and many other things.
The thing is, no one lives there. That district is entirely devoid of residential areas in fact, and with very little commercial stuff if any. All that stuff is mostly to the north, and I don't see any evidence of it being planned top-down at all, except maybe the original street layout which is largely a simple grid, with lettered streets running east-west, and a few interesting things like Dupont Circle (which probably came later).
DC is definitely not a place I'd call a "master planned city" or "artificial city"; it's evolved far too much in the last 300+ years.