An investigative measure ordered by a judge to inform the court on technical matters.
Judicial expertise is an investigative measure ordered by a judge (often in summary proceedings, or as part of proceedings on the merits) when a dispute requires the opinion of a technical expert to inform the court on questions of fact. In construction matters, the court-registered expert is tasked with observing the defects, analyzing their technical causes, identifying the parties' liability, and assessing the resulting damages.
The expert assessment is conducted under the adversarial principle: all operations (meetings, site observations, exchanges) are carried out in the presence of the parties, who may submit written observations to which the expert must respond. It generally leads to a draft report or summary note, submitted for the parties' comments, followed by a final report delivered to the judge, who alone remains competent to rule on the dispute. The expert informs; the expert does not judge.