The origin of the very red optical and infrared colours of intermediate-age ( \sim 10–500 Myr ) L-type dwarfs remains unknown . It has been suggested that low-gravity atmospheres containing large amounts of dust may account for the observed reddish nature . We explored an alternative scenario by simulating protoplanetary and debris discs around G 196-3 B , which is an L3 young brown dwarf with a mass of \sim 15 M _ { Jup } and an age in the interval 20–300 Myr . The best-fit solution to G 196-3 B ’ s photometric spectral energy distribution from optical wavelengths through 24 \mu m corresponds to the combination of an unreddened L3 atmosphere ( T _ { eff } \approx 1870 K ) and a warm ( \approx 1280 K ) , narrow ( \approx 0.07–0.11 R _ { \odot } ) debris disc located at very close distances ( \approx 0.12–0.20 R _ { \odot } ) from the central brown dwarf . This putative , optically thick , dusty belt , whose presence is compatible with the relatively young system age , would have a mass \geq 7 \times 10 ^ { -10 } M _ { \oplus } comprised of sub-micron/micron characteristic dusty particles with temperatures close to the sublimation threshold of silicates . Considering the derived global properties of the belt and the disc-to-brown dwarf mass ratio , the dusty ring around G 196-3 B may resemble the rings of Neptune and Jupiter , except for its high temperature and thick vertical height ( \approx 6 \times 10 ^ { 3 } km ) . Our inferred debris disc model is able to reproduce G 196-3 B ’ s spectral energy distribution to a satisfactory level of achievement .