Oscar Garcia has left Red Bull Salzburg to take the reins at Saint-Etienne, agreeing a two-year contract.
The 44-year-old Spaniard led Salzburg to back-to-back Austrian Bundesliga titles in his two seasons at the club and has succeeded Christophe Galtier at Stade Geoffroy-Guichard.
Garcia has signed a deal that covers the next two campaigns and arrives at the Ligue 1 side with a trio of assistants.
"Welcome to Oscar Garcia and his staff. Many clubs in Europe have congratulated us for having recruited Oscar Garcia," said Bernard Caiazzo, ASSE's chairman of the supervisory board.
"ASSE wanted an international coach capable of producing a beautiful game.
"[Club president] Roland Romeyer, [sporting director] Dominique Rocheteau and I chose Oscar Garcia because he seems to us to be the man who best corresponds to our values."
Garcia previously worked as a youth coach at Barcelona and had been linked as a potential replacement for Luis Enrique at Camp Nou.
Romeyer said: "We took the time to reflect on the choice of coach that would allow the club to take a new course in its progress.
"Oscar Garcia has the perfect profile. He is competent, as proven by his success with Salzburg, but also passionate, experienced and innovative. I am convinced that he will move ASSE forward."
Saint-Etienne finished ninth in Ligue 1 last season and were eliminated from the Europa League at the round of 32 by eventual winners Manchester United.