LargentiÃ re ( L'Argenti Ã ira in Occitan ) is a commune and sub-prefecture of the ArdÃ che department in the RhÃ ne-Alpes region in eastern France . LargentiÃ re ( L'Argenti Ã ira in Occitan ) is a commune and sub-prefecture of the ArdÃ che department in the RhÃ ne-Alpes region in southern France .