When Jean-Luc and Pierre Dardenne won the Palme d’Or for “Rosetta” in 1999 — upending such hotly fancied contenders as Pedro Almodovar’s “All About My Mother” — it wasn’t exactly an out-of-nowhere arrival. The Belgian brothers were already in their mid-forties, having begun their career in documentary filmmaking 20 years before, and had already enjoyed a fiction breakthrough with 1996’s award-winning “La Promesse.”

But it felt like an invigorating new wave all the same. Toward the end of a decade marked by auteurist flash and swagger, the empathetic, unvarnished realism of their working-class survival tale gave world cinema a clean-scrubbed human face: intent on making audiences concentrate more on the lives being presented than the directors’ style of presentation.

In a career-making performance, the 18-year-old Emelie Dequenne played a teen struggling to support herself and her alcoholic mother with fleeting, fragile jobs: Though incidentally a damning study of Belgian labour law and social welfare, the film was no political screed. With the kind of grainy everyday detail that only comes via acute human interest and observation — down to its wince-inducing depiction of period pain amid poverty — the brothers plainly distinguished themselves from the filmmakers to whom they drew immediate critical comparisons, including Ken Loach and Robert Bresson.

“Rosetta” set the pace for a joint career that would yield further delicately rough portraits of contemporary Belgian life on the social margins, not to mention numerous further prizes. Their Cannes strike rate is enviable: 2005’s shattering “The Child” — about a young, desperate father who sells his newborn infant on the adoption black market, and suffers the spiraling consequences — brought them a second Palme d’Or, launching them into an elite club of auteurs with the likes of Coppola and Haneke. 2007’s “Lorna’s Silence” saw them apply their social realist tropes to an urgent thriller format, and landed them a screenplay award on the Croisette; 2011’s “The Kid With a Bike” was a back-to-basics reset, a problem-child portrait as simply expressed as its title, and very nearly landed them a third Palme, settling for the Grand Prix instead.

If 2014’s “Two Days, One Night” got a rare shutout from the Cannes jury, it nonetheless earned the Dardennes their widest international audience to date — thanks in no small part to a mighty lead performance by Marion Cotillard, playing a factory worker given one weekend to talk her colleagues into saving her job. Though it was the brothers’ first venture into A-list star casting, Cotillard’s ultimately Oscar-nominated turn blended seamlessly into their unassuming worldview. They did the same, to less celebrated effect, with Adele Haenel in 2016’s “The Unknown Girl”; last year, with its largely unknown cast, “Young Ahmed” opted for a lower profile, though its focus on Islamic radicalization in Europe was hardly a retreat to any kind of comfort zone. Sure enough, a Cannes directing prize followed.

For all the subtle experimenting they’ve done within it, however, the Dardenne brothers’ style and outlook are among the most defined and distinctive in European cinema. Their commitment to urgent, urban Belgian portraiture hasn’t wavered: not for them an out-of-character foray into costume drama, fantasy or the English language. Their form, meanwhile, remains as rigorous as it is unadorned, to the point that the even have a signature shot, often aped by other modern social realists: a restless, close-up tracking shot of the back of a character’s head. And so we follow.