The 28-year-old had been frozen out of the Nice squad by coach Patrick Vieira, as the two never quite got on once the tactician was hired in the summer.
Balotelli turned up late for pre-season training after a summer move to Marseille stalled, and after failing to score in 10 appearances, was told he could leave.
Sky Sport Italia reports Balotelli will join Marseille for the next six months – after the striker moved off his stance of an 18-month contract – with a medical scheduled for Wednesday.
The news comes after reported interest from West Ham United and Sassuolo, but it appears the Italian international has opted to remain in Ligue 1.
Balotelli’s move to Marseille will thus end his spell with Nice, where he netted 43 times in 76 appearances in all competitions.