It reviews the origins of the practice, compares it to the Anglo-Saxon grand jury, and cites French procedural codes that establish the preliminary hearing. Details are explained regarding the composition of the presiding body of magistrates, rights and obligations of the contesting sides, procedural steps, decisional options, the deliberation process, and documentation of the hearing, its consequences, and possibilities of reconsideration. Specific instances requiring investigative hearings are delineated in terms of precedent, particularly with respect to appeals decisions. An index and excerpts from the legal codes are provided.