A process for the removal of hydrogen sulfide (H 2 S) from a H 2 S-containing gas stream through two or more serially connected catalytic reactors, which process comprises: a) mixing the H 2 S-containing gas stream with a main oxygen-containing gas stream to obtain a gas stream containing both H 2 S and oxygen, b) introducing the obtained gas stream containing both H 2 S and oxygen into a furnace whereby a gas stream depleted in H 2 S is obtained, c) transferring the gas stream depleted in H 2 S to a sulfur condenser to obtain a gas stream depleted in sulfur, d) introducing the gas stream depleted in sulfur, optionally together with a first auxiliary oxygen-containing gas stream, into a first catalytic reactor R1 containing a catalyst system which catalyzes the Claus reaction of H 2 S with sulfur dioxide (SO 2), the hydrolysis of COS and CS 2 and optionally direct oxidation of H 2 S with oxygen to sulfur, said reactor being operated at a maximum temperature T R1 max between 290 and 350° C, whereby a gas stream depleted in H 2 S is obtained, e) transferring the gas stream depleted in H 2 S to a sulfur condenser to obtain a gas stream depleted in sulfur, f) optionally introducing the gas stream depleted in sulfur obtained from reactor R1 through a series of reactors and condensers, preferably 1 or 2, each reactor containing a catalyst system which catalyzes the Claus reaction of H 2 S with sulfur dioxide (SO 2) before reaching the last reactor R of the process, g) introducing the gas stream depleted in sulfur together with a last auxiliary oxygen-containing gas stream into the last catalytic reactor R containing a catalyst system which catalyzes the Claus reaction of H 2 S with sulfur dioxide (SO 2) and the direct oxidation of H 2 S with oxygen to sulfur, said reactor being operated at a maximum temperature T R max below the maximum temperature T R1 max of reactor R1, whereby a gas stream depleted in H 2 S is obtained, h) optionally transferring the gas stream depleted in H 2 S to a sulfur condenser to obtain a gas stream depleted in sulfur, i) measuring the volumetric ratio of H 2 S/SO 2 at the exit of the last catalytic reactor R, wherein the flow rate of oxygen in the main oxygen-containing gas stream and in the optional auxiliary oxygen-containing gas streams represents 96 to 99.9 vol.% of the total flow rate of the oxygen supplemented in the process, preferably 98 to 99.8 vol.%, and more preferably 98.5 to 99.5 vol% the flow rate of oxygen in the last auxiliary oxygen-containing gas stream represents 0.1 to 4 vol.% of the total flow rate of the oxygen supplemented in the process, preferably 0.1 to 2 vol.%, and more preferably 0.5 to 1.5 vol.% and wherein the flow rate of oxygen in the last auxiliary oxygen-containing gas stream is adjusted depending on the value of the volumetric ratio of H 2 S/SO 2 measured at the exit of the last catalytic reactor R in step i) so that the volumetric ratio of H 2 S/SO 2 measured in step i) remains between 1.9 and 2.2. a) mixing the H 2 S-containing gas stream with a main oxygen-containing gas stream to obtain a gas stream containing both H 2 S and oxygen, b) introducing the obtained gas stream containing both H 2 S and oxygen into a furnace whereby a gas stream depleted in H 2 S is obtained, c) transferring the gas stream depleted in H 2 S to a sulfur condenser to obtain a gas stream depleted in sulfur, d) introducing the gas stream depleted in sulfur, optionally together with a first auxiliary oxygen-containing gas stream, into a first catalytic reactor R1 containing a catalyst system which catalyzes the Claus reaction of H 2 S with sulfur dioxide (SO 2), the hydrolysis of COS and CS 2 and optionally direct oxidation of H 2 S with oxygen to sulfur, said reactor being operated at a maximum temperature T R1 max between 290 and 350° C, whereby a gas stream depleted in H 2 S is obtained, e) transferring the gas stream depleted in H 2 S to a sulfur condenser to obtain a gas stream depleted in sulfur, f) optionally introducing the gas stream depleted in sulfur obtained from reactor R1 through a series of reactors and condensers, preferably 1 or 2, each reactor containing a catalyst system which catalyzes the Claus reaction of H 2 S with sulfur dioxide (SO 2) before reaching the last reactor R of the process, g) introducing the gas stream depleted in sulfur together with a last auxiliary oxygen-containing gas stream into the last catalytic reactor R containing a catalyst system which catalyzes the Claus reaction of H 2 S with sulfur dioxide (SO 2) and the direct oxidation of H 2 S with oxygen to sulfur, said reactor being operated at a maximum temperature T R max below the maximum temperature T R1 max of reactor R1, whereby a gas stream depleted in H 2 S is obtained, h) optionally transferring the gas stream depleted in H 2 S to a sulfur condenser to obtain a gas stream depleted in sulfur, i) measuring the volumetric ratio of H 2 S/SO 2 at the exit of the last catalytic reactor R,