Truffaut was immediately captivated by the fourteen-year-old adolescent, who had already appeared with Jean Marais in Georges Lampin's "La Tour, prends garde !" (1958). He recognized traits they both shared, "for example a certain suffering with regard to the family...With, however, this fundamental difference: though we were both rebels, we hadn't expressed our rebellion in the same way. I preferred to cover up and lie. Jean-Pierre, on the contrary, seeks to hurt, shock and wants it to be known...Why? Because he's unruly, while I was sly. Because his excitability requires that things happen to him, and when they don't occur quickly enough, he provokes them". In his final interview, Truffaut mentioned he was happy with how Léaud improvised within the flexibly written script.