"It's definitely the worst movie I've seen in Cannes"; "Sean Penn needs to stop directing"; "It's corny, bad, absolute rubbish"; "A laughable disaster" and "an appalling failure" were some of the phrases journalists bestowed on the film after its premiere.
The Last Face is the second movie for Penn as a director to be presented in Cannes after The Pledge, which also competed for the Palme d'Or in 2001.
Penn brushed aside bad reviews by critics of the humanitarian drama at a later press conference.
"I stand by the film as it is, and everyone is going to be entitled to their response," he shrugged, according to Variety.com.
"I've finished the film so it's not a discussion I'd be of value to."
Theron and Penn seemed to keep their distance at the movie's photocall, almost a year on from their last appearance as a couple on the red carpet at Cannes.
The pair posed with members of the cast firmly between them, and avoided sitting near each other at the following press conference.
The couple began dating in December 2013 and Us Weekly reported that they had become secretly engaged a year later, however the two never confirmed the reports.
- AAP