I do not think that you will find official lists of auctions on the web. I have made a quick search using the words "ventes aux enchères judiciaires immobiliaires" and I found several private links of which I am posting exemples. I cannot tell you at all how reliable they are but you might find something interresting.
Ventes aux enchres immobilires en France
La vente aux enchres en Immobilier, vente de studio, appartement, loft, maison, villa, bureau
annonces des ventes aux encheres immobilieres en rhone alpes
Ventes aux enchères