The object of this paper is to give an account in a descriptive and analytical manner the legal experience as selected members in a jury of assizes of two sociologists. Delivered testimony shows the epistemological difficulties for juror to become again sociologist at the time of the lawsuits. Anyhow the authors decipher the selection process of the jury, question the status of the proof and the credibility of the experts and point the influence exerted on the jury at the time of deliberation. This article is a contribution to the debate but does not claim to draw general laws from these singular experiences.