In Iran, it is illegal for women to attend soccer matches. Several years ago, the Iranian filmmaker Jafar Panahi’s teenage daughter begged to be brought to a game anyway. She was turned away at the entrance, and Mr. Panahi sent her home with her mother and went in. A little later, she turned up at his seat. “I acted like a boy!” she said.

The incident inspired Mr. Panahi to make “Offside,” a humane — perhaps too humane — film about Iranian girls who risk arrest, incarceration, and the crippling disapproval of their community in an attempt to pull off what his daughter did.

“Offside,” which made its American debut at the New York Film Festival, looks like a documentary: Mr. Panahi shot most of it at an actual soccer game, resorting to a bit of chicanery himself (he submitted a fake synopsis to authorities, using a pseudonym) to gain permission, and relied, as he often has in the past, on nonprofessional actors. The female cast is made up of students, many of them diehard soccer fans in real life. The young women they play are devoted to the sport but also motivated by love of their country — the match at the center of the film is a World Cup qualifier between Iran and Bahrain — and a desire to see what all the fuss is about: Having been told soccer games are no place for young women, they are naturally dying to see one.

Some make a better go of it than others. One worried-looking girl (Sima Mobarak Shahi) gives herself away at the gate and then clumsily tries to outrun the guards. Then there is the brassy, sharp-featured girl in a baseball cap (Shayesteh Irani) who exudes so much masculinity it’s a wonder she ever got caught. Both are detained, along with three other young women, behind the bleachers in a makeshift corral and under the supervision of a bored trio of army conscripts who don’t look qualified to carry water pistols.

The soldiers inform the girls they must stay put until the end of the game, when they will be turned over to the government’s feared “vice squad.” After that, they will either be thrown in jail or delivered back to their families. In Iran, as Mr. Panahi’s unsparing 2000 film “The Circle” made clear, the latter punishment is not necessarily the more clement one.

A few of the girls try to cajole and browbeat the guards into letting them go — or giving them a glimpse of the game, or at least the play-by-play. These educated Tehranis are far more assertive than their provincial captors: One of the privates (M. Kheyrabadi) is a likable simpleton, while his equally sympathetic superior officer (Safar Samandar) would rather be back in his village tending sheep.

Mr. Panahi’s Tehran is paradoxically the seat of an authoritarian government but also a place of spirited informality. Uniforms are decidedly out of fashion, strangers address one another as if they were neighbors, and few commercial transactions occur without nudging and negotiation. Early in the film, one of the girls convinces a scalper to sell her a ticket — at a slight markup, of course — after he complains she will get him in trouble, a socially illuminating give-and-take that recalls an almost identical scene from “The Circle,” in which an unaccompanied woman begged (successfully) to be allowed to buy a bus ticket.

In both films, the tickets go unused because the law — or, perhaps more accurately, the state — barges in, trumping the flexible free market of human relations that Mr. Panahi so vividly brings to the screen. Throughout “Offside,” conversations and a shared sense of national pride (the match goes to Iran) allow the girls and their captors to achieve a surprising intimacy. But this progress is stunted by the shadow of a nameless authority. The soldiers explain several times that even if they wanted to, they couldn’t let the girls go because “the chief” has a list of their names.

Mr. Panahi is known for compassionate but starkly realistic dramas that probe the hidden depths of Iranian society; he has repeatedly extracted a rich, layered humanity from a pared-down filmmaking technique. His previous works merit adjectives like beguiling (in the case of “The Mirror”), haunting (“Crimson Gold”), and shattering (“The Circle”). But “Offside” — which, unlike Mr. Panahi’s last two films, has not been banned in Iran — doesn’t pack the same punch.

Characters in those other films crisscrossed Tehran, caught somewhere between picaresque and a bad dream, and the texture of the city, from its traffic snarls to its underlit, private corners, was as engrossing as the individual dramas playing out in the foreground. “Offside,” by contrast, has a minimalist setting — backstage, as it were, at a stadium made mostly of white concrete — and a scenario with the makings of an absurdist satire. But Mr. Panahi would rather reassure us that everyone is good at heart. Why else would a petty criminal arrive late in the film to talk about his troubled upbringing and hand out sparklers?

Mr. Panahi’s latest film is a product of the best intentions. But the devil is in the details, and “Offside” could use a little more of both.