Director Jean-Pierre Gennet started the adaptation of the story together with the playwright Guillaume Laurent of "Amelie". In the process of adapting the novel, the editors need to make the story into a film, and they must make some difficult choices. Specifically, René and Roland must find a way to convert the plot of the letters in the book into the plot of the movie. In order to rewrite another important plot in the book, the two editors decided not to let Mathilde sit in a wheelchair, and turned her into a cripple who had suffered from polio. The director and the playwright spent several months together before revising the script. These revisions were also supported by the original author Sebastian Hotpeso.
At the same time, René and Roland also did a lot of investigations and read a lot of novels and materials from that era. In order to reproduce the World War I environment in the script, the two editors also collected a large number of pictures for reference. These materials are mainly derived from news reports and archives of the same period, rather than reflecting the movies of that period. For Jean Pierre, it is very important to grasp every detail. Laurent said that it is necessary to know every detail and the specific appearance of every scene described in the book of Repeso. Therefore, the main creator must do a lot of research to get as close to reality as possible
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