Brett Ratner was a hands-on member of the board for a Las Vegas swimwear company, according to court papers accusing the Hollywood director and producer of boorish behavior, including allegedly parading one model around to show off “her amazing ass.”

Ratner, who has been accused of sexual misconduct by several women, was celebrated by the execs of the supposedly ­female-friendly Bikini.com, says a worker who claims she was canned for speaking out about sexual harassment at the company.

Rather than boot Ratner, Bikini.com boss Kai-Shing Tao refused to let him step down, insisting, “I need to see [sexual harassment] in front of me for it to be proven,” former marketing manager Danielle Joyce charges in a Manhattan federal suit.

“At Bikini . . . we’re a female-friendly brand . . . I was totally behind that,” Joyce, 27, told The Post. “[But] it was pretty much the total opposite of that.”

Named as defendants are Bikini.com, parent company Remark, and Tao, but not Ratner. Lawyers for Remark denied the allegations, noting Joyce was laid off with four other workers.

Ratner’s lawyer Marty Singer called the claims involving the director “completely fabricated.”