Check out Prof. Hedy Law's essay on the opera Sapho (1795) by librettist Constance-Marie de Salm and composer Jean-Paul-Gilles Martini, newly published in The Opera Quarterly, vol. 32, no. 1 (2016). http://dx.doi.org/10.1093/oq/kbw005.
Hedy Law on the female "citoyenne" in 18th-century French opera