One of Picasso's portraits of his mistress, Marie-Therese Walter, has been sold for £28.6m at Sotheby's. The 1932 piece, entitled Femme Assise Pres d'une Fenetre (Woman Sitting Near a Window), was the centrepiece of Tuesday night's auction. Helena Newman from Sotheby's said: "This portrait is a striking and notably modern-looking work from one of the artist's most celebrated periods."