Friends of the Way of St. James the Provence-Côte d’Azur for over 10 years studying the path that joins Italy in Arles, along the ancient streets of Rome Aurelia (From Mentone) and Domitia (the Montgenevre pass).
Directions can be found on their website (www.compostelle-paca-corse.info/Chemin/chemincompostellepaca.html), but the level of detail of the maps is not particularly good. However, the route was codified by the Federation as Randonnée GR653A, and there is going to be laying the signs.
If you want to print the maps based on IGN or OSM, we can use the site Walking Pilgrim: http://maps.peterrobins.co.uk/f/menton.html.
If you own a Garmin GPS should find the route on Topofrance.
Richard and Anna Carnovailini Rastello have traveled this route on their journey to Sarzana to Somport, documented in www.camminodimarcella.movimentolento.it site.