The investigating judge may, in the course of the proceedings, order the civil party requesting an expert opinion to first pay a supplement to the deposit provided for by Article 88 in order to guarantee payment of the costs likely to be charged to him pursuant to the second paragraph of Article 800-1. This decision is made by a reasoned order that may be appealed to the Investigating Chamber. It may also be taken by the investigating chamber seized after the investigating judge has refused to order the requested expert opinion.
The additional deposit is returned if the second paragraph of article 800-1 is not applied.