In the case of a dispute with a regional, departmental or local impact, when the parties have been unable to agree on the choice of a mediator within three days of the request being filed, or when the procedure is initiated either by the chairman of the regional conciliation commission, or in the case of 2° of article R. 2523-4 by the Prefect, the latter, acting on a proposal from the Regional Director for Business, Competition, Consumer Affairs, Labour and Employment, appoints the mediator from among the persons appearing on the lists referred to in Article R. 2523-1.