Director Anna Novion Talks About Marguerite’s Theorem Following Cannes Debut

The mathematics and thought process looked quite believable. Did you study it in the past, take classes, or get immersed especially for this movie? Likewise, can you talk about the consultation work from mathematicians, researchers, or academics and how you incorporated their comments or experiences into the story? 
I’ve never been particularly good at math, but my grandmother was one of the first women mathematics academic associates. It was Ariane Mézard who did all the mathematics in the film. My scriptwriter and I had been looking for the unsolved problems of the century, and we came across Goldbach’s conjecture. We liked the pyramid shape of this conjecture as it is an easily identifiable form for viewers. So I asked Ariane if this was possible, as it was important to me for all the mathematics in the film to be accurate and realistic. What’s funny is that for the film, Ariane and other mathematicians worked on Goldbach’s conjecture and made real advances. So much so that when mathematicians try to solve this conjecture, they freeze-frame the equations in the film. It’s still a mystery to me, but it’s a delightful one.

Ella Rumpf’s performance also seems really believable as either a neurodivergent person and/or as a socially awkward “geeky” student. How was the casting process, and did she also have to study mathematics for the role?
Ella Rumpf worked enormously in her role for four months. She worked with Ariane Mézard several hours a week and with me as well. We soon realized there was no point in Ariane explaining to her the mathematics she [Marguerite] had to write as it was too complex, so she learned the formulas by heart. In order to look extremely natural on screen, she had to make math her own new language. It was a real performance. We also worked a lot on the character’s posture, how she walks, how she expresses herself, the rhythm of her speech flow, and the singularity of her view of others. All the rehearsals and discussions brought Marguerite to life and feel real. In the end, Ella and Marguerite really came together.

“…to look extremely natural on screen, she had to make math her own new language.”

The Mahjong underground games in Paris Chinatown storyline was a great addition we don’t often see. In fact, the story of a genius student playing mahjong to pay rent could have been a movie on its own! How did you come up with this idea?
At first, my scriptwriter and I thought Marguerite could play poker, but we found the idea a little too classic and déjà-vu. Then we thought of Mahjong as Mahjong champions are often mathematicians. I instantly liked the idea of the exotic beauty of the tiles, their sound being also very cinematic, and the atmosphere I could create around them. And once again, here, Marguerite would be in a masculine environment.

Anna also discussed her Cannes Film Festival experience with the film, what’s next, and Cinema influences
This is my second Cannes experience (I was at the Critics’ Week with my first film Les Grandes Personnes), and it’s still just as exciting. The film was very well received. It’s an amazing exposure for a director. The reassuring thing about being selected for the world’s biggest film festival is that you feel you are right to persist! There are many moments in a director’s life when you wonder whether it’s reasonable to fight hard to tell a story. For a while, Cannes sweeps away some of those doubts. I’m already thinking about the next film, but it’s too early to say. The more I progress in my job, the more I open up to different film genres. I’m still very attached to the cinema that made me want to do this job (Bergman, Dreyer, Ozu, Rohmer…), but as time goes by, I like to see and be inspired by different ways of making movies and different genres.