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French Food Reference Library
By an Amazon.com customer
Larousse GastronomiqueLarousse Gastronomique by Larousse Gastronomique
Buy new: $53.55 / Used from: $42.28
A feast of chauvinism and orthodoxy.  A lifetime's study.  The bible.
On Food and Cooking: The Science and Lore of the KitchenOn Food and Cooking: The Science and Lore of the Kitchen by Harold McGee
Buy new: $26.40 / Used from: $21.35
An amazing compendium of the science of cooking, for when a recipe just isn't enough.  Also very entertaining.  One of my favorite books in the world.
La Bonne Cuisine de Madame E. Saint-Ange: The Original Companion for French Home CookingLa Bonne Cuisine de Madame E. Saint-Ange: The Original Companion for French Home Cooking
Buy new: $26.40 / Used from: $16.43
The farmhouse Larousse: informative, simple, practical, surprisingly uselful.
La Varenne PratiqueLa Varenne Pratique by Anne Willan
Buy used from: $1,457.99
Complements the Larousse very nicely.  Where the Larousse is arch and theoretical and historical, la Varenne is clear, practical, and usable.  Cooking school in a book.
The Oxford Companion to FoodThe Oxford Companion to Food by Alan Davidson
Buy used from: $7.76
Not strictly French, but full of information in humorous, lucid writing.  Penguins are edible.
Larousse Encyclopedia of WineLarousse Encyclopedia of Wine by Christopher Foulkes
Buy new: $29.70 / Used from: $15.00
The best overview of wine I know.  Contains a very good compact section on food and wine matching.
The Oxford Companion to WineThe Oxford Companion to Wine
Buy used from: $13.73
Better written and edited that the Larousse Wine, maybe not as thorough.  The two books complement each other nicely.  Nice sections on Burgundy and Champagne.
Michel Roux SaucesMichel Roux Sauces by Michel Roux
Buy new: $23.10 / Used from: $18.50
Probably the best modern guide to basic saucemaking:  the recipes are clear, simple, and beautifully illustrated, often step-by-step.  Some of the sauces are classic, most are lighter.
The French Menu CookbookThe French Menu Cookbook by Richard Olney
Buy new: $19.77 / Used from: $7.95
Not really a reference book.  I include it because of it's mastery of seasonal ingredients, coursing, and wine pairing, the three bugbears of meal planning.
The Wines of the Northern RhôneThe Wines of the Northern Rhône by John Livingstone-Learmonth
Buy new: $41.30 / Used from: $29.95
A very specific reference, but I include it as the very best example of what I think a wine book should be: deep, passionate, anecdotal, food-centered, and detailed.
The Cooking of Southwest France : Recipes from France's Magnificent Rustic CuisineThe Cooking of Southwest France : Recipes from France's Magnificent Rustic Cuisine by Paula Wolfert
Buy new: $24.75 / Used from: $19.98
Actually covers about a fifth of France, and is, I think, the best English-language French cookbook in years.  Both cookbook and introduction to a vast region of rustic cuisine.
Lulu's Provencal Table: The Exuberant Food and Wine from the Domaine Tempier VineyardLulu's Provencal Table: The Exuberant Food and Wine from the Domaine Tempier Vineyard by Richard Olney
Buy used from: $34.44
One of the greatest cookbooks ever: American saint Richard Olney gives loving attention and explication to the highly regional/seasonal food of Lulu Peyraud, the doyenne of Provencal cooking and wine.
Simple French FoodSimple French Food by Richard Olney
Buy new: $12.21 / Used from: $6.71
Must have been under Alice Waters' pillow in the 60s + 70s:  it is a model of careful, loving cookbook writing, and contains the most gorgeous food writing since M.F.K. Fisher, whom Olney loathed.
Jacques Pépin's Complete TechniquesJacques Pépin's Complete Techniques by Jacques Pépin
Buy new: $16.47 / Used from: $12.83
Lots of useful, well illustrated tips from the old tradition of hotel cuisine:  how to decorate a saumon en croute, how to dress the legs of a roast goose.  That kind of thing.  Well written.
Saucier's ApprenticeSaucier's Apprentice by Raymond Sokolov
Buy new: $18.45 / Used from: $12.74
Grand old sauces in the spirit of Escoffier: glaces, demi-glaces, roux, beurre-manie, 40-quart stock pots, etc.  Beautifully organized by base and variations.  Sauce Africaine?  It's in there. 
Anne Willan: From My Chateau KitchenAnne Willan: From My Chateau Kitchen by Anne Willan
Buy used from: $26.01
I am waiting for the great Burgundy cookbook.  This is a step in the right direction.  It introduces the region, not just the recipes.
Professional Charcuterie: Sausage Making, Curing, Terrines, and PâtésProfessional Charcuterie: Sausage Making, Curing, Terrines, and Pâtés by John Kinsella
Buy new: $34.62 / Used from: $24.96
Might as well.  I made a terrine from this book, and loved it.  Sausage turns out to be a pretty easy operation.  Homemade terrines and sausages will raise eyebrows.
Culinaria France (Culinaria Series)Culinaria France (Culinaria Series) by Andre Domine
Buy used from: $34.95
Horribly written and edited by cubscouts, but a very handsome and informative overview of the regions of French food.  Beautifully illustrated.  Verify recipes before you use them.