CCFr (Catalogue Collectif de France) search holdings and addresses of almost 5,000 institutions/libraries; including BNF, Sudoc, and Base Patrimoine; search/ explore institutions by city
SUDOC catalogue du Système Universitaire de Documentation search institutions of higher education and large city libraries; SUDOC is esp. important for dissertations (theses.fr and TEL)
Bibliothèque Nationale de France (BNF) the French National Library, site of legal deposit since 1537
Regional portals to libraries and archives in France often include digital materials, but not all libraries are online.
Full-text Digital Libraries - Internet/Free of Charge
Digital Libraries - Subscription databases through Duke Libraries (many databases deposit a copy of metadata of their content in Duke Allsearch and Duke catalog)