A method of manually sorting flat articles (4) into a sorting case (7) comprising sorting slots (8) consists in generating an identification signal (100) designating a sorting slot of said sorting case, into which slot said article to be sorted is to be placed, and then placing said flat articles to be sorted in a stack and in taking the articles one-by-one from the top of the stack. The method also consists in automatically forming (310) digital images (14) of the top of the stack at a certain rate, the digital image of each article of the top of the stack including a sorting indication. Finally, on the basis of the digital image of said article on the top of the stack, the method further consists in automatically generating (330) said identification signal as a flat article is being taken from the top of the stack of flat articles.