Despite only being 19 years of age, Diousse had already played over 40 matches in top flight football for relegated Serie A side Empoli.
The French top tier side announced the signing of the Senegalese starlet on Tuesday after agreeing to a transfer fee reported to be in the region of 5 million euros.
Saint-Etienne (@ASSEofficiel) August 1, 2017
Dousse arrived in Italy as a 13-year-old and has featured 48 times in the Seria A since debuting in August 2015.
The midfielder becomes Les Verts’ third recruit since the transfer window opened as he joins Lois Diony Saidy Janko as Oscar Garcia’s new arrivals.