The invention relates to a method for determining whether or not a papillary imprint consists of living human tissue, using a papillary imprint sensor (110) comprising, superposed, a contact surface (106), an optical matrix sensor (112), and lighting means (111) formed by a plurality of mutually parallel lighting devices (1110). The method according to the invention comprises the following steps: - illuminating the papillary imprint by the lighting means, the lighting devices together forming, on the contact surface, at least one uniform lighting figure along an axis which extends on both sides of a detection surface of the optical matrix detector, and acquiring an image by means of the optical matrix sensor, said steps being implemented at least once; - in each image, selecting pixels corresponding to the valleys of the imprint, or selecting pixels corresponding to the ridges of the imprint; and - from the selected pixels, extracting an optical feature defining the response to at least one illumination, of the material constituting the papillary imprint, and using said optical feature for determining the values of at least two characteristic optical coefficients of the imprint. An imprint can thus be characterised anywhere on the surface thereof.