The movie had its big moment at the city's Film Festival, but Schrader has called her antics "unspeakable" after she apparently told him she would turn up.
He said at a press conference: "For the last 16 months I’ve been hostage, by own choosing, to a very talented but unpredictable actress. She was supposed to be here today, she said she would be, but she is not.”
He re-affirmed: "She is a great actress… but her behavior is unspeakable."
Lindsay, meanwhile, has thanked Paul on Twitter for his work on the project, saying that she wished she could be there with him.
She wrote: “I wish I could be there to celebrate with you in Venice. Paul Schrader, @braxtonpope, @JamesDeen could not have done it without you."
The Canyons picked up positive feedback from a couple of publications, but was mainly lambasted in most reviews.
Lindsay has recently completed a court-ordered 90-day stint in a rehab facility. She's been out for a month, and has already appeared as a guest host on Chelsea Handler's show Chelsea Lately.
A report was this week denied that she would be the first guest host of the new season of Saturday Night Live.