Answer
The manager of Saint-Étienne when William Saliba was sold to Arsenal in 2019 was Ghislain Printant. Printant had been in charge of the club since 2018 and had guided them to a fourth-place finish in Ligue 1 the previous season. However, the club's form had dipped in the 2019-20 campaign, and Printant was dismissed in October 2019.