INRAE, the French Research Institute for Agriculture, Food and the Environment, is a multidisciplinary institute that embraces fields that are very close to the daily, and even political, concerns of citizens. This is certainly the reason why the institute has a rich experience of more than 150 citizen science projects, with a wide variety of subjects, aims, methods, types of citizens involved, and levels of engagement ranging from crowdsourcing to participatory action research, from schoolchildren to senior citizens, from the merely curious to experienced or professional actors, etc. A better understanding of the diversity of these projects is a challenge for the institute. Indeed, the institute has a directorate for open sciences, in which our team is responsible for supporting the development of participatory sciences and science-society relations. But it is a necessary first step to identify the specificities of each large group of projects (relative to their impacts, conditions of success, training needs for researchers, etc.), helpful in better anticipating the support needed by researchers who want to engage in citizen science. The existing typologies of citizen science projects are often based on a single criterion and are therefore not well adapted to our needs. We therefore developed, via multiple discipline contributions, our own frame of reference to better qualify citizen science projects. The frame is based on 13 criteria characterizing citizen science projects that makes it possible to qualify projects without resorting to an oversimplified pigeon-holing scheme. We will present the resulting typology as well as contrasting examples of projects.