Idk, I was tempted to walk out as I started to feel I had better things to do with my time but I stayed in hopes of something crazy happening and was mostly rewarded for my patience as there are a couple bonkers scenes near the end.
Personally I didn't find the movie boring overall, but there were around five too many romance scenes between Driver and Emmanuel's characters that didn't seem to move anything forward, the kind of scenes that usually get cut for redundancy.
Old man wants to put his main actress in a sheer top, and have his director-analogue character fondle her. That's how I read those scenes. I felt like every single thing Nathalie Emmanuel did in that film was for the gratification of Coppola. He even put Nathalie in a lesbian relationship at the beginning!