From Wikimedia.
The major hint that this dress could date to 1920 is the simplicity of the over-sleeves, but there is nothing I see that is incompatible with the 1910s.
Keywords: Franzen, María Cristina Habsburg, Archduchess, Queen, Habsburg family, Borbón family, Spanish, curly coiffure, square neckline, revers, quarter length under-sleeves, elbow length notched over-sleeves, natural waistline, close skirt, floral bodice ornament, choker necklace, necklace, earrings, bracelets