The manuscripts Paris Bibliotheque Nationale fonds francais 12744 and fonds francais 9346 have long been recognized as important sources for the study of late fifteenth-century French popular song. Many of the songs found in Paris 12744 and 9346 appear to have been the basis for the so-called popular arrangements that circulated in anthologies of secular polyphony from around the same time. Scholarly editions of both Paris 12744 and 9346 have been available since the late nineteenth and early twentieth centuries, well before many other important sources of Renaissance secular music were made similarly accessible. The scattered presence of the signum congruentiae in the Paris manuscripts gives the impression that the sign is an insignificant detail, an impression that is reinforced by a nearly complete absence of any discussion of the sign in the secondary literature on these sources.