A Woman Sleeping With Her Stepson? This Director Knows It May Shock.

When the French director Catherine Breillat was 40, her then-husband and the father of her first child ended their relationship to be with a much younger woman. Soon after, Breillat started dating a man 12 years her junior.

“Men want to repudiate their wives of a certain age by saying they couldn’t be loved by anyone anymore,” Breillat said in a recent video interview via an interpreter. “But for me that’s not true. I want to tell other women there’s no cause for despair.” In “Last Summer,” which comes to theaters Friday, she probes at this realization through an incendiary premise.

Since the 1970s, the lauded director, now 75, has repeatedly focused her unflinching gaze on the troubled sexual awakenings of girls, often in the uncaring hands of older men, but in “Last Summer,” that dynamic is inverted: A middled-aged lawyer, Anne (Léa Drucker), risks her career and marriage by having a clandestine affair with her 17-year-old stepson, Théo (Samuel Kircher).

The film, Breillat’s first in a decade, joins several recent movies concerned with the power dynamics of heterosexual couples in which the woman is older, including the lighter Anne Hathaway-vehicle “The Idea of You” and Todd Haynes’s divisive “May December.” (Haynes’s movie was inspired by the true story of a teacher who started a relationship with one of her students.)

According to Breillat, this wave of films reflects a simple reality. “It’s the truth,” she said: “Young people are attracted to older women.”