Arbration exists where the parties refer to third parties the resolution of purely legal questions, such as the interpretation of the contract, the determination of its validity, or the assessment of its effectiveness. Conversely, a contractual expert determination exists where the parties refer to third parties the mere ascertainment and assessment of technical data, such as the existence of the loss, the value of the damaged property, and the estimation of the indemnity, undertaking to accept that assessment as a direct expression of their contractual will.
A contractual expert determination does not constitute a derogation from judicial jurisdiction and does not prevent the parties from having recourse to the court for the resolution of disputes involving legal questions, since such disputes are excluded from those referred to the experts.
A contractual expert determination, having the nature of a joint mandate, may be challenged solely on the grounds of defects of consent under art. 1427 of the Civil Code or on the grounds of nullity of the contract under art. 1418 of the Civil Code.