Hemp lime concrete (HLC) is an environment-friendly material increasingly used in building construction. Many studies have focused on the moisture buffer capacity of HLC, but its pollutant buffering capacity remains unknown. To address this research gap, the potential for moisture and toluene buffering capacity of hemp concrete is presented in this article. The sorption capacity toward toluene (TOL), a typical indoor volatile organic compound (VOC), of HLC has been measured and investigated with a 50 L environmental chamber at 23°C and a relative humidity of 50%. Moisture buffering capacity of HLC has been determined according to the Nordtest protocol. The experimental data have been used to evaluate the model parameters of the CHAMPS-bio model (Coupled Heat, Air, Moisture and Pollutant Simulation transport model dedicated to Bio-based building materials) that assesses VOC transfers and hygrothermal behavior of building materials under dynamic conditions. The results are innovative and new for hemp concrete, and evidence that this bio-based material can mitigate the indoor toluene concentration and regulate indoor relative humidity thanks to its buffering capacity.