"Collective Folie" is a work conceived for the Parc de la Villette by Japanese artist Tadashi Kawamata. About twenty meters high, this first tour that the artist has designed in Paris, has evolved over many workshops bringing together high school students, students and volunteers. In dialogue with Bernard Tschumi's "Folies", the tower takes shape over accumulations and impromptu arrangements, in the sharing of ideas and efforts with the artist, by dressing the structure carrying pieces of wood. recycled. The film restores this adventure through the testimonies of the different actors of the project and the reactions of workshop participants as well as visitors to this "collective madness". In her text, the art critic Emmanuelle Lequeux gives us her analysis and gives us the stakes of such a proposal. Echoing this installation, the book also offers a perspective of ten other projects of towers built by the artist throughout the world