Abstract: Maxime Du Camp intervened in two ways in the genesis of Flaubert's L’Éducation sentimentale. First, he gave him a lot of information during the writing of the novel. Then he sent him twelve pages of remarks about historical and stylistic details. Based on their correspondence and manuscripts, this study analyzes Du Camp’s dual contribution, showing how he helped Flaubert during the writing as well as with his reading after the completion of the novel.