If the judge considers that he has insufficient information on points that can be clarified by a visit to the premises or if it appears to him that the parties’ claims differ on such points, he shall visit the premises on the day and at the time decided by him, if necessary in the presence of a consultant.
However, if he considers that purely material observations are sufficient, he may appoint any person of his choice to carry them out.
If the differences relate to points of fact that cannot be settled without recourse to an expert opinion, the judge shall appoint an expert whose mission shall relate to the factual elements enabling the criteria defined, as the case may be, in articles R. 145-3 to R. 145-7, L. 145-34, R. 145-9, R. 145-10 or R. 145-11, as the case may be, and on the additional questions submitted to him by the judge.
However, if the judge considers that the expert’s mission should be limited to investigating the impact of certain elements only, he shall indicate those to which it relates.