This is Luise-Alexandra, Gräfin von Bernstorff, daughter of Johann Heinrich, Graf von Bernstorff who was the German ambassador to the US between 1908 and 1917. Her father lost the diplomatic campaign to influence US foreign policy regarding World War I with Britain. He turned to supporting sabotage activities including an unsuccessful attempt to bomb a bridge connecting towns in the US and Canada and a successful attack on a munitions shipping activity on Black Tom Island near New York City. The near-kiloton range explosion also damaged the then recently completed Statue of Liberty.
From old-picture.com/american-legacy/005/Bernstorff-Countess-LA.htm; monocolor tint removed. Also posted to the Belle Époque - 1890 to 1914 Album here.
A woman with a good figure could show it off wearing a dress without a waistline that hugged her curves, as seen here, around 1910. She wears long gloves. Her dress could come from Germany, France, or the US.
Keywords: Harris & Ewing, Luise-Alexandra, Gräfin von Bernstorff, von Bernstorff family, von Pourtalès family, Löwenstein-Wertheim-Rosenberg family, Countess, bouffant coiffure, necklace, pouter pigeon half bodice, sweetheart neckline, quarter length full sleeves, arm band, flared cuffs, no waistline, close skirt, flounces, train, ribbons, gloves