The 22-year-old Italian was caught smoking by a ticket collector while travelling with his AC Milan teammates on a high speed train to Florence for yesterday's match against Fiorentina.
Coaches have been trying to get Balotelli to quit smoking for years and the practice is banned on Italian trains.
The ticket inspector reported Balotelli to AC Milan chief executive Adriano Galliani and told him: "You need to pull his ears. He was smoking in the bathroom."