Sophia Loren, right, and Ibrahima Gueye in “The Life Ahead.” Regine (aka Greta) de Lazzaris/Netflix

Simone Signoret won a César award for her performance in the 1977 film “Madame Rosa,” which leads to an inevitable question when it comes to making “The Life Ahead”: Why bother?

Like “Madame Rosa,” “The Life Ahead” is adapted from Romain Gary’s novel “The Life Before Us.” Unlike the earlier version, this one features Sophia Loren in the lead role. Which answers the “Why bother?” question. When Loren says she thinks she might be right for Madame Rosa, you listen to her. And you make the movie.

In this case, the filmmaker who listened was Loren’s son, Edoardo Ponti, who has directed “The Life Ahead” with understated skill, attention to atmosphere and old-school humanistic values. The story is a classic: Madame Rosa, now transplanted from La Pigalle in Paris to a seaside town in Italy, is a former prostitute who serves as a caretaker and mother figure for the children of her erstwhile colleagues in the sex-work industry. One day, she is asked to take on a particularly challenging case: A 12-year-old Senegalese immigrant named Momo (Ibrahima Gueye), with whom she has immediate, volatile chemistry. The two fight, tussle and argue, two wounded souls who, when they finally begin to let their guards down, are much more alike than different.

For Madame Rosa, this means disclosing a secret she’s kept buried for decades, as well as another, more recent one that’s obvious to anyone paying attention. At 86, Loren inhabits the role with both vulnerability and majesty: As one of our final links to cinema’s Golden Age, she is simply magnificent, both physically and in terms of her craft. In many ways, “The Life Ahead” harks back to the actress’s finest work with her mentor, Vittorio De Sica, not only by way of its historical memory of World War II, but in its plea for tolerance and mutual understanding.

A creeping sentimentality threatens “The Life Ahead” at nearly every turn, and some departures into magical realism don’t always work. (Ponti co-wrote the script with Ugo Chiti and Fabio Natale.) But as long as the film is focused on Madame Rosa and Momo and their unlikely friendship, it’s on rock-solid ground. One of Loren’s greatest strengths as a movie star has always been her generosity as a collaborator, and that’s on full display from the moment Madame Rosa meets her antagonist-turned-protege, with Loren and Gueye developing their own utterly unforced rhythms and rapport. Gueye makes an impressive debut as a man-child who is equal parts tough and heartbreakingly needy; always attuned to those conflicting currents, Loren infuses every interaction with her singular brand of sensitivity, dignity, world-weary loss and maternal compassion.

“The Life Ahead” might be a familiar story, but as a showcase for Loren’s sensuality, star power and unfailing instincts, it feels both classic and exhilaratingly new. She’s still got it, and as this performance reminds us at every turn, she always did.