TORONTO -- Canada's entry in this year's best foreign-language Oscar race, "Rebelle" ("War Witch"), is filled with -- and surrounded by -- paradoxes.

The most obvious is in the plot, in which child soldiers in Sub-Saharan Africa are forced into horrible situations at a time when they're making the transition to adulthood and experiencing such hormone-fuelled feelings of first-time love.

Kim Nguyen, the film's Montreal-born writer-director, says he sensed such contradictions -- of despair and resilience, madness and humanity -- during his time in Congo, where he shot the unflinching drama last summer.

"The funny thing is, when you're in Congo you hear about these really hard stories, tough stories, and yet they're the most festive people I've ever met," Nguyen said in an interview at the recent Toronto International Film Festival, where "Rebelle" screened.

"We'd do amazing parties and not think about tomorrow, and it was just a pleasure to be there, although it was a struggle. So you do see that, in conflicts, war-ridden countries: there are still the simple jealousy elements of a boy and a girl."

Another paradox surrounds "Rebelle" star Rachel Mwanza, whose teenage character is forced to fight with, and become a sex slave for, a rebel commander (Montreal's Alain Lino Mic Eli Bastien). Fellow newcomer Serge Kanyinda co-stars as the militia group's albino magic man, who falls in love with Mwanza's character and wants to save her.

Mwanza had never acted before shooting the French-language film, and her moving performance has earned her prizes at the Tribeca and Berlin film festivals.

But as she and "Rebelle" are feted at splashy galas around the world, the 15-year-old -- who was abandoned by her parents and used to live on the streets in the Congolese capital Kinshasa -- continues to face challenges there.

"The Congo is not an easy place to live and to grow up in and unfortunately she doesn't have a stable family life," said the film's co-producer, Marie-Claude Poulin, of the production company Item 7.

"We've set her up for school and to live with someone but it's never as easy as it looks."

"Rebelle," which won the best narrative film prize at the Tribeca Film Festival, opens Friday in limited release in Toronto and Ottawa.

Nguyen wrote the film over 10 years, getting the idea from an article about nine-year-old Burmese twin brothers who led an army of rebels.

He didn't set the story in any particular country because he didn't want to cast any judgments or statements about Africa, he said.

As part of his research, Nguyen met with ex-child soldiers in Burundi and spent two months in Congo ahead of filming in Kinshasa, which he called "one of the most difficult, most challenging cities to be living in right now in the world."

"I think at least 25 per cent of the script was modified by just being in the Congo and seeing stuff," he said.

Nguyen cast mostly non-actors from Kinshasa and didn't give them a script. Instead he explained the story and let them improvise.

Mwanza's fearlessness of living in the streets "gives her that effervescence in the way that she acts," he said.

"There's something about kids in the streets ... when you're with them, they're kind of always looking over their shoulder and I guess they always have an eye open, even when they're sleeping, and this turns out to be a great quality to have when you're acting," added Nguyen.

"I think what defines a great actor is the way that he lives in the silences, when he's not saying anything and he's conveying so much. And these kids from the streets, the ones that were good at it were really, really good at it -- and Rachel was the best one of them."

Bastien, who studied acting at the Montreal School of Performing Arts, was in awe of Mwanza's talent.

In one harrowing scene at the beginning of the film, he had to deliver Mwanza her cue to cry, and "you never saw a kid cry like this," he recalled.

"It took me off guard," said Bastien, who is of Haitian heritage. "I was like, 'Huh?'And she was bawling.

"She was really crying for that scene and made that scene real, and I was like, 'You know what? I've got to step up my game."'

Bastien's jovial personality is the polar opposite of his frightening character.

To prepare for the role he studied online video clips of rebel chiefs.

On set, he stayed in character as much as possible so he would be believable to the non-actors in the film. But off set he and the rest of the Canadian cast hung out with the locals, including Mwanza.

"They were really kids from the streets basically and they were telling me about their lifestyles," he said. "Then I was like, 'Where do you live?' 'This is it, this is where I live.' I'm like, 'Really?'

"The thing is that they're ... smiling living through it."

Kanyinda took a great liking to Bastien, who had to learn how to speak his lines in the local Lingala language for the part.

"He was the crazy one," he said with a laugh. "He was the one showing me all over. He even had his ear pierced because he was like, 'I want to look like him.' ... He changed his style just to be like me."

Bastien said when he returned to Canada, he was struck by how easy life is here.

"I came back a changed man."