Chris Brown, Yella Beezy Sued For Alleged Assault Backstage on '11:11' Tour

Chris Brown 's "11:11" tour has been marred by some serious thuggery ... according to a new lawsuit accusing the singer of orchestrating the assault of several men.

According to legal docs, obtained by TMZ Hip Hop, Brown, Yella Beezy , CB's entourage lieutenant Sinko Ceej and Live Nation are all facing a lawsuit filed by the 4 alleged victims ... who are seeking a whopping $50 million.

CHRIS BROWN'S 11:11 TOUR

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Brown's "11:11" tour hit Dickies Arena in Fort Worth, TX on July 20 -- and after the show let out, plaintiffs Larry Parker , Joseph Lewis , Charles Bush and Da Marcus Powell say they were invited backstage and escorted there, along with 40 women, for a post-concert hang.

The plaintiffs say it took Chris 30 minutes to enter the VIP area, where they'd grown tired of waiting and began to make their exit ... but not without saying goodbye to the guest of honor.

According to the suit, Bush says he dapped up Chris, congratulated him on a good show and received appreciation from the "Under The Influence" artist.

Then, Bush claims a member of Brown's entourage shouted loudly, "Man you don't remember you two were beefing?" and claims Chris replied, "Oh yeah, we were. What's up, n****? I don't forget sh*t" and verbally ordered his crew to give Bush the beats.

In docs, Bush claims he was surrounded by 7-10 of Chris' chums who punched and kicked him. He also claims an entourage member known as Hood Boss threw a chair at his head.

The plaintiffs also allege Chris sent Yella Beezy and co. to "f*** up" Parker, chasing him into a dead-end staircase with a locked door.

Parker says he was punched and kicked in his head for more than 10 minutes after Chris encouraged all of his companions to get a piece of the action.

All 4 men say they suffered severe injuries and had to undergo various medical treatments. Their attorney Tony Buzbee says at least one of them remains hospitalized and vowed to bring CB to justice.

In addition to the $50 mil in damages, the plaintiffs have also filed for restraining orders against Chris, Beezy, and Sinko Ceej.

We reached out to Chris and Beezy's camp, but, nothing back yet.