An investigative measure entrusted by a court to a listed technician, conducted contradictorily, whose report does not bind the court yet decides it in practice.
A court-ordered expertise is an investigative measure by which a judge instructs a technician to advise on a question of fact the court cannot settle itself. It differs from a private assessment on three points that make all the difference: the expert is appointed by the court rather than by a party, is entered on an official list and subject to a challenge procedure, and the work is contradictory, each party being able to attend, produce documents and file written observations the expert must answer. Its scope is bounded, since the expert is forbidden to express legal opinions, but the line is porous and many reports cross it. The report does not bind the court, which stays free to depart from it with reasons, yet it determines the outcome in the great majority of technical cases. An interim application allows one to be ordered before any trial, on the sole condition of a legitimate reason, and that is how most construction litigation begins. The problem solved is the court's technical incompetence on questions that decide the law.
Article 238 of the French Code of Civil Procedure forbids the expert from expressing legal opinions, and article 145 allows an expertise to be obtained before any trial where there is a legitimate reason to preserve or establish evidence of a fact. That second route is how most construction defect files open in France, often years before the first substantive claim is filed.
expertise ordonnée par le juge, référé expertise