Oval.
During the 40 year period from 1778 to 1818 vigee Le Brun painted 37 self portraits. 17 were originals and 20 were copies.
This copy of the Academy of St. Luke (Rome) self portrait is located in the Museum of the Art, Verviers, Belgium.
[http://www.batguano.com/vigeeselfp.html#O]