Bio-based insulation materials have recently been replacing classical ones for their lower production energy and ecological properties. However, these materials might be an important source of Volatile Organic Compounds (VOCs) due to their organic load. Therefore, we measured VOC surface emissions in a public building, a school, insultated with a bio-based insulation material, namely cellulose wadding. Two seasonal (winter and summer) field campaigns were carried out in an elementary school located in Carvin, north of France. Using two Field and Laboratory Emission Cells (FLEC), VOC emissions from the six surfaces in this room were characterized: floor, ceiling, and the four walls, among which three were exposed to the exterior and contained cellulose wadding. About 50 compounds were quantified in total during summer and winter. These compounds were predominatly alcohols, aldehydes, and acids. Results showed that total surface emissions in summer are two to five times higher than those obtained in winter with the highest emission rates coming from the floor (46 µg.m-2.h-1), followed by the three walls containing bio-based insulation material (30 µg.m-2.h-1), the ceiling (11 µg.m-2.h-1). The lowest emissions came from the fourth wall, without cellulose wadding (6 µg.m-2.h-1). VOC emissions from the three bio-based walls were comparable; however, the emission rates of certain compounds were slightly higher from the wall exposed southeast during summer and winter. Building products constitute a major source of indoor pollutants. Moreover, even if bio-sourced insulating materials might be energetically a good substituent for mineral-based materials, their impact on indoor air quality must be taken into consideration.