Street casting — the process of plucking non-professional actors from their everyday lives to play prominent screen roles, often as observationally scripted versions of themselves — is a process that has yielded rich rewards for many a French film in recent years. Titles from Laurent Cantet’s “The Class” to Frédéric Baillif’s “La Mif” have thrived off the vibrant spontaneity of their enterprisingly sourced young ensembles, but how often is a degree of exploitation the price paid for such diamond-in-the-rough authenticity? A lively, spiky and elastically metatextual debut feature from Lise Akoka and Romane Gueret, “The Worst Ones” asks this and other questions of a practice it too perpetuates: The internal artistic conflict that ensues is very much the point.

A surprise winner of the Un Certain Regard prize at Cannes in May, “The Worst Ones” thoughtfully applies the filmmakers’ shared background in casting to its somewhat inside-baseball premise: a film-within-a-film that wittily traces the chaotic pre-production and production trials of an indie feature shot on location in the working-class coastal town of Boulogne-sur-Mer in northern France. Those casting credentials help ground Akoka and Gueret’s industry-focused argument in credible accountability, but they also come to the fore in the film’s own expert use of non-pro talents: an irresistible quartet of young discoveries whose sharp, literally lived-in performances make the best case for the defense.

Not that “The Worst Ones” is set up in strict rhetorical terms. Casually structured and sometimes breezy in tone, it gestures toward hard satire in its depiction of the manufactured “grittiness” pursued by many film artists in the country’s tradition of banlieue cinema — but a prevailing sense of affection, not limited to the kids at its center, somewhat mollifies the film’s ethical inquiry. Akoka and Gueret first addressed these ideas in their César-nominated 2016 short “Chasse Royale”; its expansion has been several years in the making, entailing years of casting and workshopping in working-class northern France, making “The Worst Ones” a sort of mirror document of its own development.

The film’s fictional counterpart, then, is the unpromisingly titled “Pissing in the North Wind,” a belated debut feature for middle-aged Flemish artist Gabriel (an amusing Johan Heldenbergh) that resembles a po-faced parody of the social realism perfected by his compatriots the Dardenne brothers. A character study of a pregnant teen and her peers, it’s light on script, depending heavily on what its amateur stars can bring to the table. “The Worst Ones’” own title refers to the locals’ bewilderment at the casting process when the production rolls into their suburban housing project: They could pick anyone, and they chose those kids?

Neighbors may not see the scrappy talent in Lily (Mallory Manecque), Ryan (Timéo Mahault), Jessy (Loïc Pech) and Maylis (Melina Vanderplancke), but that’s their loss. Handed the tricky dual assignment of playing their characters both in actor mode and as “themselves” when the cameras are off, they’re a remarkable collective, seemingly cast to personality type but with canny performance instincts of their own.

The problems come when Gabriel either doesn’t trust those instincts enough, or counts too much on their naïveté. Discomfiting scenes of him goading the naturally short-fused pre-teen Ryan to lose his cool for a fight scene, or inappropriately coaching a love scene between Lily and Jessy — with no intimacy coordinator on set — encourage viewers to wonder just how much insensitive engineering goes into the “natural” performances we marvel at on screen. One assumes Akoka and Gueret handle their vulnerable non-pro actors with rather more delicacy and care, but “The Worst Ones,” with dark humor and occasionally confrontational candor, still gives us room to query the industry conventions in which it is complicit.

To what extent the actors are playing themselves is for them to determine: Certainly, Gabriel’s screenplay appears to hinge on certain bleak classist stereotypes to which they may not entirely relate. Those skeptical locals, furthermore, voice their resentment of outside observers like Gabriel for presenting their lives in an unflattering light, for the sake of art. It’s not all teenage pregnancies and social decay in Boulogne-sur-Mer — would it kill the filmmakers to seek out the community’s points of pride? Conscientious and self-effacing, “The Worst Ones” doesn’t entirely absolve itself of similar charges, though it does find artistry and honor where others tend not to look.