Cyperus fauriei is a perennial sedge that grows from somewhat tuberous rhizomes enveloped in reddish-brown fibers. The culms are solitary or clustered, standing 10–50 cm tall and measuring 0.5–2 mm in diameter at the base. These stems are trigonous (three-angled) and smooth in texture. The leaves are simple and alternate, with linear blades that range from shorter to slightly longer than the culms, measuring 1–3.5 mm in width. The blades vary from soft and flexible to somewhat stiff. Leaf sheaths are reddish brown, and stipules are absent. The margins of the leaves are entire. The inflorescences are umbelliform, simple or partially compound, and form moderately dense, subcapitate clusters with shorter rays ranging from 0 to 1.7 cm in length. The entire inflorescence spans 2–4 cm long and 3–10 cm wide. There are typically 3–10 spikelets per inflorescence, arranged in an ascending to spreading fashion and cylindrical but narrowed at the base. Occasionally, 1–2 short lateral spikes are present at the base of a primary spike. Each spikelet is 0.8–3 cm long and 8–10 mm wide and contains 7–9 flowers. Involucral bracts number 3–5 and are significantly longer than the inflorescence itself, with the lowest bract ranging from 6–20 cm long. The spikelets are oblong-lanceolate to linear-lanceolate in shape, 4–8 mm long and 1–1.5 mm wide, and become strongly spreading with age. Their apex is acute, and the rachilla is winged. Glumes are thick but membranous, pale yellowish brown with reddish brown flecks or lines, and moderately densely imbricate. Each glume measures 2–3 mm long and 1–1.6 mm wide, with an obtuse to truncate apex and a green keel that extends into a recurved mucro. The flowers are bisexual and lack petals. Each flower contains three stamens and a superior ovary. The fruit is an ellipsoid, trigonous achene approximately 1.2 mm long and 0.7 mm wide. A single seed, with a thin seed coat free from the pericarp, is present. The embryo is basal, and the endosperm is abundant. It is found in dry, mesic, and possibly subalpine forest habitats between 300-1,830 meters.