The disgraced singer faced an L.A. Superior court judge on Tuesday as he was given a five-year probation order, as well as six months of hard community labor after he was convicted of assaulting his former lover in February.
He was also ordered to stay away from Rihanna for the same period of time and to report for community duties within 72 hours of sentencing.
However, Brown shocked fans by showing little remorse over the vicious attack by heading for a night out on the town at West Hollywood hotspot Guys and Dolls.
The star even grabbed the mic during Michael Jackson's hit "Dirty Diana" and told the crowd: "There was only one King of Pop. We love you, Michael."
Now he is facing a possible investigation into his actions -- as, at 20 years old, he is too young to enter nightclubs and bars in America, according to strict drinking age limits.
The venue he frequented had a Type 48 liquor license, meaning it is only a bar or club and not a restaurant.
Los Angeles Probation Department spokeswoman Kari Webb tells E! News, "It (breaking probation) won't be taken lightly. If you break the law, you're in trouble."
Despite Brown sticking to water throughout the evening, his entourage ordered 10 bottles of champagne, and he would have only been allowed to stay in the club if he was hired as a performer.
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