Inside

• The debut feature of Alexandre Bustillo and Julien Maury, made on a budget of 1.7 million euros (about $2.5 million) and confined almost entirely to a single suburban house to stretch the money.
• It premiered in the Semaine de la Critique (Critics' Week) sidebar at the 2007 Cannes Film Festival before touring genre showcases including the Toronto International Film Festival and Fantastic Fest; it opened theatrically in France on June 13, 2007.
• Beatrice Dalle plays the intruder, credited only as 'La Femme' (The Woman); Alysson Paradis, the younger sister of singer-actress Vanessa Paradis, plays the pregnant Sarah.
• Background TV news footage runs the real 2005 French banlieue riots throughout the film, and when Sarah calls for help the police are too tied up with the unrest to reach her in time, sharpening the title's inside/outside double meaning against the era's immigration-and-identity politics.
• The German release was trimmed by nearly two minutes to soften the worst of the gore, but even the cut version was seized and effectively banned in Germany for 'glorification of violence,' sending fans to the uncut Austrian edition.
• Hollywood took years to land a version: a Spanish-shot English-language remake directed by Miguel Angel Vivas (with Rachel Nichols and Laura Harring) premiered at Sitges in 2016 and surfaced on US VOD in January 2018; Bustillo and Maury were approached and both turned it down.

Read the two women as the same person split in time. Sarah is the mother who still has a future to lose; La Femme is what grief does to a mother who already lost hers in the same crash that opens the film. The siege isn't a home invasion so much as Sarah being hunted by the version of herself the night is trying to turn her into.

The 2005 riots on the TV aren't set dressing. The violence kept 'outside' the wealthy suburb on the news is the same violence that comes 'inside' Sarah's door, and the responding cops fail her exactly the way the state failed the banlieues. The horror is that the wall between the comfortable interior and the burning exterior was never real.

The ending is a perverse birth allegory played straight. Every weapon in the house is domestic and feminine, and the final delivery is performed by the wrong mother with the wrong tool. The film argues that the line between creating life and destroying it is thinner than the genre usually lets us pretend.

Four months after the car crash that killed her husband, a pregnant photographer named Sarah waits out a bleak Christmas Eve alone, her labor scheduled for morning. Then a woman in black knocks, knows her name, and won't leave. What follows is a siege built around one obscene want: the stranger doesn't want to kill Sarah so much as open her and take what's growing inside. Bodies pile up at the door as the night collapses into a red-lit war between two mothers, one of whom was never going to walk away whole.