He was born in Amiens and then he moved to Paris to study Literature at the University of Paris. During the short time Pascualina lives in Paris he has a romantic and unforgettable relationship with her. He is her first official boyfriend and becomes a very important person to her as this relationship marks her transition from childhood to adolescence. Gustav has a bohemian and intellectual personality and plays a fundamental role in Pascualina´s growth as he helps her to know herself better and to express her feelings. He listens carefully and pays real attention to her as Pascualina is able to make him feel noble emotions. Pascualina feels deep gratitude and admiration towards him, however, after moments of joy and enthusiasm Gustav gets lost in thoughts with strong feelings of guilt exacerbated on one hand by the relationship he has with his mother who reproaches him having abandoned his home and on the other by his former girlfriend Filomene who manipulates him with her frequent anorexic crisis that force her to be hospitalized. The constant changes in his character have turned him into an indecisive person with no clear aims in his life. He ends walking always from people as he did with Pascualina.