According to Delcourt (p.117, note 1) 1778 is the date given by Pierre Prévost in the introduction to Hécube, published in his 1782 Les Tragédies d'Euripide, but the earliest available copy is dated 1783. See Delcourt, Marie. Etude sur les traductions des tragiques grecs et latins en France depuis la Renaissance. 1925, p.117.