This page focuses on the French language, and covers some major collections in France and the French-speaking region of Belgium. The Library of Geneva is included here, but please see the Germany, Austria & Switzerland page for other libraries in Switzerland.
The Bibliothèque de France has been working with other libraries to create a unified searchable catalog of French libraries, but the rare books collections may not always be integrated into collective catalogs like these. Similarly, WorldCat may or may not list all of the older materials held in various libraries, but it may provide a helpful first indication of where your materials can be found. Individual libraries usually still maintain their own catalogs, which are the most reliable source of information about their holdings. Even then, old and rare books may not be cataloged online.
If you're not sure what you're looking for, perusing printed bibliographies is a good place to start. More information on searching for texts can be found on the home page of this guide.
Searching online catalogs is the fastest way to find what you're looking for if you already know what it is. If you want to explore, browsing bibliographies may be the way to go. Many paper bibliographies are available under Z call numbers, and in facsimile editions via Google Books and HathiTrust. More information on bibliographies can be found on the home page of this guide.
Several catalogs of French printed books divided by century are available. Below you will find two catalogs of books printed in the sixteenth and seventeenth centuries, as well as some more specific catalogs by genre, and some early bibliographies.
The National Library of France began as the royal library, with its origins in the fifteenth century. The Royal Library of Belgium began during the same century. As a result, both national depositories hold enormous collections of early printed books.
When requesting access to old and rare materials, most institutions will require that you apply for some sort of researcher's card and may require to see some evidence of why you need to use the materials. It is a good idea to anticipate this, and familiarize yourself with the requirements at the libraries you intend to visit before you travel. It is also advisable to bring an original letter from your department chair or dissertation advisor attesting to your research needs.
More information on visiting libraries and archives can be found on the home page of this guide.
In addition to the national libraries, many regional public libraries, university libraries, and private libraries in France, Belgium and Switzerland hold important collections of early printed books. These are just a few of the major collections.
For libraries in North America with collections of early printed books from Western Europe, please see the Collections in North America page of this guide.
As Susan Baddeley writes in Orthographies of Modern Europe, in the sixteenth century "the French language had an extremely rich phonological system, and only the 23 letters of the traditional Roman alphabet to write it with. This led, inevitably, to a large number of ad hoc adaptations, consisting mainly of added letters (diagraphs, mute letters), with all the ambiguity and sometimes obscurity that resulted." This spelling instability makes reading early modern French books an exciting, but sometimes frustrating, adventure.