Process for preparing chlorine from hydrogen chloride, which comprises the steps: a) feeding of a stream a1 comprising hydrogen chloride and of a stream a2 comprising oxygen into an oxidation zone and catalytic oxidation of hydrogen chloride to chlorine, giving a product gas stream a3 comprising chlorine, water, oxygen, carbon dioxide and inert gases; b) cooling of the product gas stream a3 and removal of water and hydrogen chloride as aqueous hydrochloric acid, leaving a gas stream b comprising chlorine, water, oxygen, carbon dioxide and inert gases; c) optional drying of the gas stream b) to leave a gas stream c which is substantially free of water and comprises chlorine, oxygen, carbon dioxide and inert gases; d) at least partial liquefaction of the gas stream c and of a chlorine-rich recycle stream f1 comprising chlorine, oxygen and carbon dioxide by compression and cooling, giving an at least partially liquefied stream d; e) gas/liquid separation of the stream d into a gas stream e1 comprising chlorine, oxygen, carbon dioxide and inert gases and into a liquid stream e2 comprising chlorine, oxygen and carbon dioxide; f) feeding of at least part of the gas stream e1 into a membrane separation unit and fractionation by membrane separation to give the chlorine-rich recycle stream f1 and a gas stream f2 which is low in chlorine and comprises chlorine, oxygen and carbon dioxide and recirculation of the chlorine-rich recycle stream f1 to step d); g) separation of the liquid stream e2 by distillation into a chlorine stream g1 and a stream g2 comprising essentially oxygen and carbon dioxide.