In 1911 Octave-Jacques Gérin (1875-1937), professor at L'Institut Commercial de Paris and C. Espinandel, a graduate of l'École des Hautes Études Commerciales, issued
La publicité suggestive: théorie et technique as part of the monograph series "Commerce et Industrie: Les Procédés Modernes de Vente." As far as I have been able to determine, this was the first book to apply hypnosis, or the power of suggestion, to marketing, and was an early example of applied psychology. The preface (in French) was written by Walter D. Scott, Director of the Laboratory of Psychology at Chicago. Examples given in the first and second editions apply entirely to the widest variety of print advertising, and appear to exclude radio.
Digital facsimile of the expanded second edition (1927) from BnFGallica
at this link.