Data monitoring by citizen scientists in the field of biodiversity is mainly achieved for free, since citizen science is primarily carried out by amateurs who are not paid for what they report. This lack of remuneration has been claimed to be either exploitative by those who study inequality of access and participation in amateur circles, or empowering by those who promote new digital solutions for naturalist reporting. In that respect, Faune France, a major citizen fauna database in France, represents a renewed relationship between amateurs and the general public through their contribution to this digital initiative. In contrast with explanations in terms of personal motivation or social stratification, participation in Faune France reveals a special attachment to the subject -birds, butterflies, frogsand the obligation toward nature felt by contributors, shown by their desire to pass on their observations digitally to recipients who are for the most part unknown. Rather than a means of 'luring' amateurs when they give away information, commitments such as Faune France reporting is based on attachments to nature and others, and cautiousness in information disclosure. Data are given to an indeterminate other, be it a distant scientist or other participants on the internet. Hence the stress in this study on data sensitivity (given that the final destination of the data is unknown and there is a risk of it being misused), and on responsibility seen from the point of view of the contributing naturalist.