Bleu
Bleu (French), blue; Bleu céleste, sky blue or mountain blue; Bleu de France, s. Berlin Blue; Bleu mourant, »dying blue«, flat, pale blue (Germanized Blümerant); Bleu Sèvres, s. Pâte sur pâte; Bleu verdâtre, synthetic mountain blue.
The Saxon Seven Years’ War uniforms pictured here (Infanterie-Regiment Prinz Xaver von Sachsen left, and Grenadier-Bataillon Kurprinzessin above) are white with pale blue facings.
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909