Intermediation contracts belong to a category of contracts founded in trust pursuant to the Roman Trust. In the Antique Rome, the transfer of property to a third party was effectuated by a ritual in virtue of which, the trustee undertook to hold and subsequently return the property to its original owner. This ritual was not juridicised and gave way to much reflection on its juridical qualification if any. It is in light of these interrogations that this paper seeks to do the same in a contemporary context which raises the same questions. Which is the law applicable to intermediation contracts and what role does it play in light of the particular role played by the relation of trust in such contract?