The notions of quantity and intensity are prominently present in the French lexicon. Their characterization has remained, however, at the level of intuition. This study attempts to define them more rigorously, starting from the observation that they are facets of a single notion, the degree, whose definition encompasses the concepts of ‘measure’ or ‘dimension.’ Thus, numerous adverbs may denote either quantity or intensity (tellement), while other adverbs, some primarily suitable for quantity (beaucoup), and some, for intensity (très), function as free or contextual variants. We will also distinguish between pure degree markers (combien) and markers in which the degree combines with other semes (loin, longtemps). Moreover, these adverbs do not form a homogeneous semantic or syntactic class. Some are markers of the extent of a degree (beaucoup), others, of the conformity or equality of a degree (assez, trop) or of emphasis (si). Other properties, such as argumentative orientation (peu, un peu), precision vs. vagueness (trois, beaucoup), levels (weak, medium, high: peu, pas mal, beaucoup), and numerosity (peu, un peu), divide the adverbial inventory in various subsets.