- 9 volumes of correspondence published between 1926 and 1933:
ONE OF 50 COPIES ON CHINENumbered and initialled by the publisher, the only large paper edition.

- 4 volumes of unpublished correspondence published in 1953:
ONE OF 90 COPIES ON VELLUM PUR FIL, only large paper.

Produced with the help of René Dumesnil, Jean Pommier and Claude Digeon, this edition is the first attempt to publish Flaubert's important correspondence in an exhaustive and demanding manner. After a first attempt by Charpentier - supported by the author's nephews - which was partial, faulty or deliberately truncated, followed by the Centenary edition, Louis Conard revised, corrected and completed 1992 letters for the correspondence and 1,296 previously unpublished letters for the 1954 supplement.

The publisher was well aware of the value of such a venture: "The letters to Louise Colet appear in full for the first time... If you have the time, Madame, I recommend reading Princesse Mathilde's little study. Her rendering of Flaubert is strikingly true. "letter to Hélène de Hérédia-Doumic, 1927.

This edition, which remained a reference for over 20 years, is probably the last to be printed on large paper. The important Pléiade edition, published from 1973 to 2007 - 4,273 letters addressed to 279 correspondents - and its impressive critical apparatus, has unfortunately lost all bibliophilic pleasure.