Elle Fanning on ‘Sentimental Value,’ Learning to Say No and Finally Making ‘The Nightingale’ With Dakota

Elle Fanning’s first arrest came at a Sabrina Carpenter concert. Just an hour before leaving for the show, she received a text: “Getting arrested tonight. Dress accordingly.”

The mock arrest, captured on the big screen for all concertgoers to see, was worth it.

“At least it was a joint arrest,” Fanning laughs, referring to sharing the experience with her sister Dakota. “If it’s going to happen, might as well happen together.”

It’s fitting that Fanning approaches even staged arrests with grace and humor, because in Joachim Trier’s “Sentimental Value,” she plays Rachel Kemp, a Hollywood actress who must learn the hardest lesson of all: how to walk away from something she desperately wants.

The role came as a surprise. “I was a big fan, obviously, of ‘The Worst Person in the World,’ like everyone,” Fanning says. “You think of directors, and you think, ‘Yeah, Joachim, he’s on my bucket list,…