Gaston Bachelard agreed to become an Honorary Trustee of the Institute of General Semantics in 1940. (1) Bachelard’s 1934 book Le Nouvel Esprit Scientifique, which Korzybski had gotten, already showed the French epistemologist as a compatible formulator.
Since he had written that book, Bachelard had come to know Korzybski’s work and to give it considerable importance. The following excerpt (part of a larger discussion of Korzybski and his work) comes from the English translation of Bachelard’s 1940 book La Philosophie du Non: Essai d’une philosophie de nouvel esprit scientifique. (A translation of this done by a student of Korzybski, G. C. Waterston, was published in the U.S. in 1969 as The Philosophy of No: A Philosophy of the New Scientific Mind.):
Those of us who are trying to find new ways of thinking, must direct ourselves towards the most complicated structures. We must take advantage of all the lessons of science, however special they may be, to determine new mental structures. We must realize that the possession of a form of thought is automatically a reform of the mind. We must therefore direct our researches towards a new pedagogy. In this direction, which has attracted us personally for a number of years, we shall take as our guide the very important work of the non-Aristotelian school, founded in America by Korzybski, which is so little known in France. …The psychological and even physiological conditions of a non-Aristotelian logic have been resolutely faced in the great work of Count Alfred Korzybski, Science and Sanity,... [p. 108]. (2)
(1) In 1939, Korzybski had taken up the idea (probably proposed by M. Kendig, his 'right hand woman' at the Institute of General Semantics) to invite a group of well-known academics, professionals, government officials, etc., to have their names associated with Korzybski as "Honorary Trustees" of the Institute of General Semantics and thus to express their support of the aims and program of the Institute. Honorary Trustees had no official duties.
(2) You can link here to the earlier (1953) J. Samuel Bois translation of Bachelard's full discussion of Korzybski and His Work in The Philosophy of No. The Bois translation appeared in General Semantics Bulletin 12 & 13.