Expert appraisals are often crucial in legal proceedings concerning liability in matters of public health. Experts are required to reconstruct facts or to appraise the work of colleagues who act in an advisory capacity to policy-makers, in order to establish whether the quality of the expert studies and advice provided have been adequate to the importance of the health issues. In France, expert witnesses have an official status subject to a regulated procedure that includes specific and regular audits. Although this procedure clearly identifies the competences of court-appointed experts, it is far too lengthy and cumbersome for researchers to gain access to this status. Clearer procedures capable of distinguishing expert appraisals from lobbying also need to be established.