Though Vianne and Isabelle experience hardship during their adolescence due to the death of their mother and subsequent abandonment by their father, they nevertheless enjoy many of the comforts of their upper-middle class background, growing up in a spacious family home and receiving an expensive education. In contrast, Gaëtan’s life is marked by poverty. A tough, sharp young man who has spent time in prison, he was raised in a single-room home without running water, and he is forced to turn to crime in order to get by. While Isabelle is motivated by a desire to emulate her heroes, such as Edith Cavell, Gaëtan’s motives are more explicitly political. Upon first meeting Isabelle, he proclaims himself a communist, and he has many connections among the left-wing Resistance groups in Paris and Carriveau. In the later years of the war, he joins a Partisan militia group, bombing German targets and disrupting their operations. His willingness to employ violence offers a contrast to Isabelle’s humanitarian efforts.  

His relationship to Isabelle is an important narrative thread in the novel. They initially bond over a shared desire to participate actively in the war effort, but Isabelle is crushed when he abandons her in Carriveau, leaving a note that states that he does not believe she is ready for war. Though he attempts to shield Isabelle at first, he nevertheless aids her in her journey to join the Resistance, putting her name forward to Henri and vouching for her in the Resistance group in Paris. He keeps a close eye on Isabelle for much of the novel but shows a reluctance to enter a romantic relationship with her. For Gaëtan, war is no time for love. He pushes Isabelle away when she attempts to get closer to him, reasoning that either of them might die at any moment due to their illegal activities. Ultimately, however, he accepts Isabelle’s argument that, given the dangers they face, they must seize whatever time they have together. He becomes a source of solace to Isabelle during the most dangerous period of her work with the Resistance and brings peace to her final days in Carriveau. In 1995, he attends the passeurs reunion, where he tells Vianne that he never stopped thinking about Isabelle, even naming his daughter after her.