WASHINGTON (AFP) - Hip hop star Chris Brown is to stand trial on Sept 8 for allegedly hitting a fan outside a Washington hotel after lawyers failed to agree on a plea bargain.

The date was set by Judge Patricia Wynn in District of Columbia Superior Court where Brown appeared - despite hot summer weather - in a smart leather jacket, shirt, tie and khaki trousers.

The Grammy-winning R&B artist was charged with misdemeanour assault after an altercation outside a hip hotel in the US capital with a fan who wanted a photo with him.

At the time, Brown, 25, was still on probation following his 2009 conviction for assaulting his then-girlfriend, pop diva Rihanna.

Defence lawyer Mark Geragos told reporters that as part of a plea bargain, federal prosecutors wanted Brown to read aloud a statement of facts "that wasn't true." He didn't elaborate.

Striking a plea bargain could have spared Brown - whose sixth studio album X is due out this year - the risk of spending up to six months in jail and a US$1,000 (S$1,250) fine.

His bodyguard Christopher Hollosy, 35, has already been found guilty of assault in the same incident, following a separate trial. Wynn told him to return Nov 7 for sentencing.

Hollosy was on the job on Wednesday, guiding Brown through a swooning posse of female fans outside the court house towards a black SUV limousine waiting at the curb.

Just three weeks ago, Brown exited Los Angeles County jail after serving 108 days of a year-long sentence for violating the terms of his parole in the Rihanna domestic violence case.

Celebrity website TMZ said he benefited from a reduction in sentence for good behaviour and time he spent in a rehabilitation facility.