This is a painting by Francois Boucher titled The Marquise de Pompadour. Boucher painted many portraits of Pompadour over several years. This painting, she was actually painted to look younger than she was. In this painting you can see the use of more pastel colors, and the more relaxed normal poses they started to use in the Rococo era. You can see she is also wearing a corset, and ruching on the sleeves.