The legend is probably a reference to her work in World War I and adopts Elisabeth of Bavaria as emphatically Belgian.
From eBay; seller's mark removed with Photoshop by gogm.
Elisabeth wears a coat with broad lapels over a wide-lapelled Chanel-esque dress in this colored card.
Keywords: Queen Elisabeth of Belgium, Elisabeth Gabriele in Bayern, Elisabeth Gabriele Valérie Marie, Herzogin in Bayern, Élisabeth en Bavière, reine des Belges, Wittelsbach family, Wettin family, Princess, Queen, bouffant coiffure, chemise, low neckline, blouse, vee neckline, collar, lapels, coat, buttons, fur boa