One of the things I enjoy most about my current job is when I discover resources such as this, which I spotted from a post to the French Studies Libraries Group e-mail list by Teresa Vernon of the French Collections at the British Library. She describes the Catalogue Collectif de France, the CCF, (not the Combined Cadet Force of my schooldays) in particular the Base Patrimoine, 2.5 million entries for pre-1914 items, from 63 regional bibliothèques municipale and specialised library catalogues.
From the CCF home page, in the left-hand column click each of the following in turn: Localisation > Rech. spécialisées > Base Patrimoine
I wonder why we haven't managed to build anything like this in Britain

