He was fined 1.8 million euros ($2.13 million).
The 2014 World Cup champion, who appeared in a Munich court in a dark blue suit, is accused of injuring his ex-girlfriend during a holiday brawl in 2018.
The mother of his twin daughters accused Boateng of throwing a lamp at her causing her to slip and then throwing a small cooler that injured her arm before hitting and pulling her hair.
Boateng has denied injuring his ex-girlfriend.
The 33-year-old centre-back spent 10 years at Bayern after joining Manchester City in 2011, winning nine Bundesliga titles and two Champions League trophies. He signed a two-year contract with Lyon, Ligue 1 last week.
