Baccarat crystal champagne glass, Nancy pattern.
Baccarat's catalog of the year 1916 (you can download this catalogue from our website) :
Not signed before 1936, they use to get a paper sticker:
Height: 11,5 cm
Diameter: 9,5 cm
Period: made before 1936 because not signed.
Here is a converter inches / cm to help you with the dimensions: