I cannot locate information about her.
From bbc.co; enlarged by one half by gogm.
The Duchess appears to be dressing or undressing in this portrait. She has a partially undone jacket bodice revealing a plain corset over her chemise that extends beneath the bodice.
Keywords: Batoni, Duchess Sforza Cesarini, Duchess, Italian, straight coiffure, cap, jacket, fur, long tight sleeves, cuffs, square neckline, chemise, corset, jacket bodice, buttons, peplum, earrings, wrap