Denis's Traité is of special interest because it offers one of the first detailed descriptions of functional keyboard temperament to have been written by a practitioner rather than a theorist. Among French sources, Guillaume Costeley had described a system identical to one-third comma meantone in 1570, but only in reference to an experimental nineteen-note octave. He provided no account of the actual tuning procedure and his ideas, as will be seen, were somewhat outside the mainstream of eventual developments in France and in Europe as a whole. Titelouze had made a brief reference to the necessity for keyboard temperament in the Preface to the Hymnes de l'Eglise (Paris, 1623), but he provided no details, instead referring his readers to the writings of earlier theorists (‘les bons auteurs’). Mersenne had discussed keyboard temperament in exhaustive detail in the Harmonie universelle, but there is little evidence in his writings to suggest that he had ever tuned a harpsichord himself. Indeed, his lack of direct familiarity with tuning procedure may well have led to the confusion that crept into his instructions for setting quarter-comma meantone temperament.

Through Denis's frequent references to his temperament system as ‘our’ tuning and ‘our familiar harmonic tuning’, we may infer that he clearly has in mind the system of common practice during his day. Unfortunately for modern readers eager for enlightenment and definitive answers, his description of the temperament he recommends with such enthusiasm is not precise.