Throughout the world, in urban areas, scientists have observed the homogenization of the biodiversity. Furthermore, urbanization and modern lifestyles have greatly reduced people's knowledge of and interaction with nature. Both have grave consequences for the conservation of the biodiversity. Here, we present the construction and the implementation, by a wide range of actors, of a park focused on urban biodiversity, the Parc Urbain des Papillons (PUP). The collaborative construction of this park associates, on one hand, experimental research on rethinking management practices to encourage the reestablishment of biodiversity in the city and, on the other hand, active training, mediation and exchanges for a range of publics (environment managers, students, schoolchildren and the general public). The interest of this kind of programme lies in the collaborative aspect, allowing considerable enrichment through the exchange of experiences between the various actors and publics. We conclude by pointing out that this experimental park provides extensive opportunities for sharing science differently and for developing learning, training and outreach programmes overlooked in urban areas.