Finette was a can-can dancer.
She was a can-can dancer at the Bal Bullier in Paris during the 1850s, and modelled to JW for an etching (Finette (K.58)). In 1866 she brought her troupe to London where they caused quite a sensation in the Lyceum pantomime; photographs of her were sold in the print shops.
Kennedy, Edward G., The Etched Work of Whistler, illustrated by reproductions in collotype of the different states of the plates, New York, 1910; MacDonald, Margaret F. et al, Whistler, Women and Fashion, New Haven and London, 2003, pp. 55-8.