The synthesis gas stemming from biomass gasification contains particles (ashes, soot, etc.), which, if not removed, can induce severe operational damage. The problem is more serious if syngas must be used for chemical synthesis as in the Fischer-Tropsch catalyst reaction or the water–gas shift. The particles contained in syngas can reduce or inhibit the catalyst effect. Moreover, for energy reasons, it is also necessary to develop a filtration process at as high a temperature as possible. To address this issue, a study to show the possibility of removing the particles from syngas with an electrostatic precipitator at high temperature (500–1000 °C) and pressure (0.1–1 MPa) was conducted. Syngas filtration tests conducted directly downstream of a gasifier demonstrated the feasibility of implementing an electrostatic precipitator to clean syngas at temperatures above 500 °C.