From Google search; removed spots with Photoshop and monocolor tint.
Maria Antonia's dress may be under a mantle edged with ruching along the center and above the arms where it is also edged with lace.
Keywords: Maria Antonia of the Two Sicilies, Maria Antonietta Giuseppa Anna, Maria Antonia Anna di Borbone-Due Sicilie, Maria Antonietta delle Due Sicilie, Maria Antonietta di Toscana, granduchessa di Toscana, Princess, Grand Duchess, Borbone family, Italian, straight coiffure, floral headdress, earrings, bodice, high neckline, lace collar, bows, lace-edged mantle, ruching, bracelets, crinoline