Considering the hypothesis that intervals of fourths work in Debussy's Étude pour les Quartes as an every-level structuring cell, this article proposes a harmonic analysis where all chords are drawn from a twelve-tone quartal space. The hypothesis is that Debussy tests the capacity of the quartal matrix to supersede conventional triadic harmony. On another hand, because of this novel networking, the high-level formal articulation demands complementary resources to be more effective, especially concerning perception. For this reason, in a second phase, an analysis of secondary dimensions, such as density and relative range, is attempted to highlight their function. The conclusion points to "unsolved" interactions between the lower- level harmonic system, which recycles some aspects of the tonal rhetoric, although in an experimental quartal space, and a surface that avoids sensation of both continuity and causality.