François Boucher. Resting Girl - Louise O’Murphy (‘Ruhendes Mädchen - Louise O'Murphy’), 1751 (Wallraf-Richartz-Museum, Cologne).

Oil on canvas: 59.5 x 73.5 cm. Model presumed to be Marie-Louise O'Murphy (1737-1814), mistress to Louis XV. Later version at the Alte Pinakothek Munich (with brazier and a single rose): here. 

Visit > Wallraf-Richartz-Museum, Cologne.
More > François Boucher at Wikipedia.
More > Marie-Louise O'Murphy at Wikipedia.