To research the subject, writer/director Jeanne Herry couldn't take part in actual meetings of restorative justice, given that they are supposed to be a safe place, and nothing that is said there is meant to be told elsewhere. So instead, she went through three formations, which she felt were very insightful: the one which Fanny and Michel go through in the movie, the one to be a mediator, like Judith in the movie, and one in Québec via Zoom.
Jeanne Herry doesn't really do rehearsals, but she has one-on-one readings with each actor, to make sure there is no issue with the script and that they're okay with the lines. But once this is done, this is it, there are no ad-libs or changes, as every hesitation, every comma, every "well" or "so" is already written in the script.
While writing the movie, Jeanne Herry wondered whether to show the attacks or not. While watching the French TV series En thérapie (2021), she realized that it was a better idea to leave the violence out and let the audience make up their own images in their mind.
Jeanne Herry wrote the script with several actors in mind, some of them having already been part of her previous movie, In Safe Hands (2018): Gilles Lellouche, Élodie Bouchez and her real-life mother, Miou-Miou.