Former Bath coach Mike Ford will leave Toulon at the end of the season.
The French side said Ford had decided not to activate the option for an additional season in his contract and he will be replaced by Fabien Galthie.
After being initially recruited as an assistant coach, Ford took over from Diego Dominguez in October last year following the club's poor start to the season.
Toulon, currently fourth in the Top 14, won the European Cup three times from 2013-15.
A Toulon statement read: "Mike Ford wishes to commit himself to another project from next summer but will fulfill his role until the end of the season with the utmost professionalism and seriousness."
Galthie, a former France scrum-half who has coached Stade Francais and Montpellier, has signed a two-year deal to take over as director of rugby and will be assisted by Fabrice Landreau and Marc Dal Maso.