How Oscar-nominated Butterfly used an unusual technique to achieve its beautiful art style

I felt a deep need to tell his life story through that final swim, as a plunge into memory. This film invites us to reflect on issues that are still very present today, such as antisemitism, racism and fear of others. It shows how these dangerous tendencies can weaken our societies, and by recalling the tragedies of the Second World War, it underscores the importance of remembrance.

It also highlights the revocation of citizenship, an aspect that is far from insignificant. This question strongly resonates with contemporary debates, particularly around migration policies. It is crucial to remind ourselves how unjust and life-altering such measures can be.

This technique gives me great freedom. The texture of the paint, the grain of the canvas, the visible brushstrokes bring a very particular warmth and depth.

Above all, painting makes transitions easier: I can transform a face, move Alfred from one age to another, or shift him from a memory into the present with great fluidity. Underwater, bodies become more abstract; at the surface, they are more defined. I prioritise movement and sensation over precise drawing.

However, it is a long and demanding process. Each shot is complex to create, especially when depicting water — the sea, a swimming pool, or a river each require different approaches. The slower the movement, the more difficult it is to animate.

The preparation was quick. I very soon knew how I wanted to tell this story and make the film. The actual production required two months for the sets and 100 days of animation.

Three of us worked on the animation, followed of course by post-production. We completed the film in one year.

Water is truly at the heart of Butterfly, and representing it was one of the film’s greatest challenges. I wanted every key moment of Alfred’s life – whether joy, achievement, or pain – to be connected to water, like a thread running through his entire story.

To achieve this, I used a slightly different technique from the one in my feature The Crossing: the backgrounds are painted on canvas, which gives a richness and density of texture that glass alone would not provide, while the water itself is animated either on glass to achieve transparency and fluidity, or directly on canvas to benefit from colour blending.

I always animate directly under the camera, which allows me to gradually transform the paintings, let movement emerge progressively, and create images from the materials as they appear during the process. Some shots were particularly difficult because each type of water has its own nature: the sea, swimming pools, rivers, or basins.

Colour was central to my approach. With my production designer, Margaux Duseigneur, we created a specific palette for each period of Alfred’s life, almost like an emotional colour chart.

For example, a sky blue for childhood, turquoise blue for adolescence, navy blue for maturity, and a violet-tinged blue for his final dive. The Auschwitz scenes are rendered in dull, muddy, greenish, almost dirty tones.

Each colour corresponds to a memory, a specific moment, and works on the viewer at an unconscious level. It was a deliberate choice to support the story and emotions in a subtle and coherent way.

The most difficult scene to create was the arrival at the concentration camp and Nakache’s separation from his wife and daughter, because I didn't know how to represent it. It's extremely difficult to depict such traumatic events without falling into voyeurism.

As I mentioned earlier, very slow movements are also challenging to animate. The dive into the Auschwitz basins to retrieve the bread thrown to him, as well as the shot where he sinks into the water, required a great deal of work and patience from the animator who created them.

I can mainly speak about French animation, which I know well. There are more and more films of very high quality, both features and shorts. When I started, there were very few animation schools in France. Now there are programmes all across the country. The young directors coming up today are extremely talented.

However, the animation sector is quite concerned about the rise of artificial intelligence. I believe it is important to continue producing inventive films that move beyond traditional techniques and affirm the importance of artistic craftsmanship.