The evolution of the thermal stability of the materials during the composting process was assessed by Thermo-Gravimetric Analysis (TGA) using a Mettler TGA2 apparatus (Mettler Toledo, USA). Thermal analyses were performed from 25 °C up to 800 °C at 5 °C/min under nitrogen flow (20 mL/min). An average weight of 10 mg was used each time, if possible, with regards to the available quantities, measurements were duplicated. Because this measurement was destructive but needed at least 10 mg of mass, it was carried out on mixed samples of different size classes.