Stéphanie Chuat and Véronique Reymond’s “My Little Sister” (“Schwesterlein”) premiered at the Berlin Film Festival on Tuesday to strong critical and audience receptions, with particular praise heaped on lead actors Nina Hoss and Lars Eidinger.

In his Variety review, Guy Lodge praised: “This is bright, unaffected naturalism with a fluidly roving camera, but also a generous regard for its ensemble.”

Both working actors themselves, Chuat and Reymond wrote what they know with “My Little Sister,” a film that kicks off in, and depends heavily on, Berlin’s theater scene as a place where its characters find themselves feeling most energized.

Focusing primarily on twins Lisa (Hoss) and Sven (Eidinger), the story is a gently told tale of affection between two siblings going through the greatest struggles of their lives. Lisa has been away from her home in Berlin for too long, supporting her husband as he spends a term as the headmaster of an elite boarding school in the Swiss Alps. Sven, one of Berlin’s top stage actors, is just out of hospital after chemotherapy treatment for leukemia. When their mother proves woefully unfit to care for Sven, let alone herself, the actor joins Lisa, her husband and their two children in Switzerland, where he realizes that she is suffocating creatively.

While Sven’s future health is anything but certain, he’s already outlived his initial prognosis, he dedicates himself to reinvigorating his little sister’s ambitions and pushes her to find a part of herself she’s lost in the years since leaving Berlin.

Produced by Ruth Waldburger at Vega Film AG, world sales for the film are handled by Beta Cinema.

Chuat and Reymond talked with Variety ahead of the film’s premiere about their working relationship, writing from an actor’s point of view and recalling personal experiences crafting a narrative.

Place is key to your story. You have lead characters that are attached to certain places where they flourish: the theater, Berlin, rural Switzerland or flying through the air, and tend to wither when they are removed from them. What role did that play in writing?

Reymond: We first wanted to broaden our horizons and write a script for non-French speaking actors because we want to work with great German, Danish, British or American actors we love, without being limited by language. In terms of places, we chose the Swiss mountains and the boarding schools because there are many expats there, many foreigners cut off from their roots. It’s an interesting milieu to explore.

There is a bit of autobiography to this film: You’re actors and writers, and I read that Stéphanie, you have firsthand experience caring for a family member suffering from cancer. How much of the film is drawn from personal experience, and how much was invented?

Chuat: It was strange indeed that we were imagining this twin story, where one would care for the other, at nearly the same time my mother was diagnosed with a stage-4 lung cancer. She passed away 10 months later. During this period, I couldn’t be involved in the writing since I was the caregiver for my mother, but Véronique continued writing, and I inserted some of my personal experience in the characters’ relationship. But the most autobiographical part of the movie is inspired by the precious relationship between Véronique and I, as we’ve known each other since childhood, and there is a lot of our connection in Lisa and Sven’s bond. As a creative duo, we also have this question: “What would I do if the other one is gone?”

Music and sound are used to great effect throughout the film to not only set the mood, but sometimes replace dialogue altogether. Was that the plan when writing, or did that come later?

Reymond: This idea was already there during the writing process. We wanted to have pure musical moments in the movie in order to take a step back for a few minutes, while the characters are caught up in their conflicts, arguing or whispering something that the audience doesn’t hear. We understand everything though, and we can feel their emotions even stronger. During the editing process, we had the feeling that the movie needed more of these sequences with no dialogue, because the characters are intense and it’s important to take a breath from time to time. These musical moments make that possible.

How do you think your acting careers influence your writing/filmmaking?

Chuat: Being actresses is a big asset in our relationship to actors on the set, because we share the same language and we love to explore the colors of their role with them. In the writing process, we work a lot from the characters’ perspective, trying to feel their motivations from the inside, speaking from each of their points of view, in order to increase the emotional stakes. Our movies are definitely character-driven stories. Also, before shooting, we both play the scenes on set in order to define the positions of the camera according to the dramaturgical stakes. We then propose a kind of choreography to the actors and it’s up to them to adjust it, to integrate it and make it their own.

There is an irony to the film’s title “My Little Sister.” Lisa and Sven are twins, but Lisa is clearly the caretaker for the family as evidenced by their mother’s inability to care for herself. One gets the impression that Lisa has been the head of the house for much of her life, yet despite those few minutes between their deliveries she hardly seems the “Little” sister.

Reymond: Well, as Sven says to Lisa in one of the core scenes of the movie, “You were born two minutes after me!” But joking aside, it’s true that Lisa is the responsible character. She manages the family, makes all the phone calls for her brother and helps him to get back on stage. But looking at it from a different perspective, you can see that Lisa is deeply fragile because she lost herself in caring for others. Her whole journey is about getting back to her creative source. Her twin brother knows it, and as he declines, he gives everything to get her back to herself. In that moment, Sven becomes the big brother.

This is a story told in extreme close ups. The handheld camerawork makes it feel almost like watching exceedingly well shot home movies. How important is the perspective of the camera to delivering this intimate narrative?

Chuat: The way the film is shot echoes the characters’ inner restlessness. There is something that vibrates underneath this apparently ordinary daily life, something that pulsates in their blood. We wanted images in motion, because motion is life. There’s a tension, a beat that brings life to the film. The camera is almost another character in the movie, following the action. When you decide to shoot a whole movie with a shoulder-mounted camera, working on the focus is also essential; it guides the viewer’s vision throughout the scene. In the same vein, we use a lot of one-shot scenes that allow the actors’ performances to shine.

What’s next? Both for this film, and for you?

Reymond and Chuat: We have several feature projects, among them “Toxic,” a new series in development which takes place in Switzerland and New Zealand. It’s an ecological thriller combined with a family drama exploring the consequences of a mysterious contamination of Lake Geneva. But to be honest, these days, we are pretty much focusing on our “Schwesterlein” premiered at the Berlinale!

Pictured, Top: Stéphanie Chuat and Véronique Reymond; Bottom: ”My Little Sister.”