1858 or 1860 Mme Wienczyslawa Juriewicz, née Mlle Barszczewska by Franz Xavier Winterhalter (private collection)
I checked this image against the next one several times. Winterhalter painted four portraits of her, two in 1858 and two in 1860. Eugene Barilo von Reisberg's list only has the next image and not any of the other three, including this one. That forced me to look for the mole above the left side of her lips; that mole is barely visible in the next image.