“Susanne Bartsch picked up where [Andy] Warhol left off,” RuPaul Charles says of his friend, the woman he says set him down the path to become Supermodel of the World. He’s not the only one: Performance artist Joey Arias credits Bartsch with encouraging him to try drag, transgender pioneer Flawless Sabrina speaks of her in the same breath as Warhol, and fashion historians trace London style’s expansion to New York and Tokyo in the ’80s to Bartsch.

As for the woman herself, she’s still throwing parties.

While dressing for one of her fabled Tuesday night parties at Meatpacking district club Le Bain, Bartsch was fretting over the colors for one of her outstanding looks: “It’s not really pink,” she says. “I mean, I know it’s pink, but it’s not a pink that I feel pink in.”

It’s an auspicious introduction to Bartsch’s world, well chosen as the opening scene in “Susanne Bartsch: On Top,” the stylish debut documentary from queer filmmaking duo Anthony Caronna and Alexander Smith, who go by the moniker Anthony and Alex. The film, which takes its title from Bartsch’s Le Bain parties, is the opening night selection at Newfest, New York’s LGBT film festival.

Originally hailing from Switzerland, Bartsch speaks in a heavy German accent and loathes tardiness — both in herself and others. “Where the fuck are you?” she barks at her assistant, before he saunters casually into the party, directing costumed performers onto ornate pool floats. Later, she instructs him to stop tapping on a list with a pencil so as not to make marks. In another scene, she tells her make-up artist: “This look, I hate it.”

“She does not walk into a room unnoticed,” David Barton says admiringly of his ex-wife. Bartsch married the New York gym mogul in a lavish wedding in 1995; archival footage of Bartsch in a nude body suit, wrapped entirely in a cocoon of white tulle is one of the film’s more amazing finds. (As is the revelation that the wedding was sponsored by Playboy). Other precious archival footage includes a very young RuPaul gallivanting in New York bodegas and emceeing Bartsch’s nights at the Copacabana in the late ’80s.

The film charts Bartsch’s history with sufficient detail, touching on her complicated family life in Switzerland, her mark on the fashion world, and her early and steadfast commitment to AIDS activism. The film’s most impressive interview subject is Bartsch’s college-aged son, Bailey, who offers a candid peek behind the fabulous curtain with a wisdom beyond his years. “It’s weird to be around Susanne when she’s playing Susanne,” he says, using his mother’s first name. Bailey addresses the difference between the “character” and the real person with a measured frankness. “I think appearing as a normal person is a source of vulnerability for her. She doesn’t want to be normal, she wants to be more than that.”

“I would never want to walk into a fabulous event not with a wig and a look,” says Bartsch. “I think I would feel less interesting.” Of course, she is terribly interesting, look or not. “No one can throw a party like her, no one carry on like her, no one’s personal life is as interesting as hers,” says Michael Musto, who has dedicated his life to writing about New York’s gay culture and nightlife. “She’s endured for 30 years.”

There are plenty of events and settings to keep the film just as interesting as its subject — from preparing her closet for a retrospective at The Museum at FIT to a fascinating look at her ornate apartment inside the fabled Chelsea Hotel. These grand moments are peppered with an intimate window into a more domestic life, like Bartsch shoving a chicken in the oven with a ceremonious, “Back in the oven, bitch!”

As the film’s techno score swells to an overwhelming frenzy during one of her events, the music stops short as Bartsch answers a call from her son. Her voice lightens, her face brightens, and she shouts over the clamor of adoring fans: “This is all for you. You give me a purpose to leave a legacy.” In Anthony and Alex’s capable hands, the Susanne Bartsch legacy endures just as brightly as it began.