The interest in thermo-conversion of Solid Recovered Fuels (SRFs) processes for syngas production has increased in the last decades. However, the monitoring and control of trace contaminants in SRFs such as chlorine in syngas still meet difficulties. The aim of this study is to determine the gas composition and to track the chlorine content in the products from the pyrolysis and oxidation of SRFs. Two types of SRFs from two different industrial sites in France were chosen for this study. The first one, SRF1, was chosen for its low chlorine content (0.3 wt% of Cl) comparing with the second one, SRF2 (1.1 wt% of Cl). SRF1 with low chlorine content showed that the most of Cl was transferred into the gas phase during thermo-conversion process. SRF2 with high chlorine content showed more NaCl in the residual solids after the reactions than its initial inorganic chlorine content