Landscape designer and professor at the Collège de France and the Ecole Nationale Supérieure de Paysage de Versailles. He is the author of several works and concepts that marked the actors of the landscape at the end of the 20th century and the beginning of this century, including Jardins en mouvement, Le jardin planétaire and Le Tiers paysage. Le Tiers paysage designates all the spaces which, neglected or unexploited by man, present more natural richness in terms of biodiversity. These concepts stem from the observation that a natural landscape is never fixed and that species and genes must circulate. Gilles Clément is also in favour of the crossbreeding of species, which he rather calls “brassage”, and which has been interwoven over the ages. Hence the idea of planetary gardens and forests that he cultivates as a protector, considering with the same benevolence the “wild grasses” that try to grow on the cobblestones of cities and the rarest species planted in prestigious gardens.