Process for producing an olefins-containing hydrocarbon product comprising ethylene and propylene by conversion of an oxygenates-containing reactant mixture, which is divided into a plurality of reactant mixture substreams, in a multi-stage oxygenate-to-olefin synthesis reactor, comprising the following steps: (a) providing the multistage OTO synthesis reactor having a plurality of serially connected reaction sections in fluid connection with one another comprising a first reaction section and at least one subsequent reaction section which each contain catalyst zones comprising solid catalysts that are active and selective for OTO synthesis, wherein upstream of each catalyst zone a feeding apparatus for a reactant mixture substream is arranged and wherein the last reaction section in the direction of flow is in fluid connection with a conduit for discharging an OTO synthesis reactor product, (b) introducing a reactant mixture substream into each reaction section via the respective feeding apparatus, wherein the at least one subsequent reaction section is additionally supplied with the product stream from the respective upstream reaction section, introducing at least one steam stream into at least one reaction section, introducing at least one recycle stream into at least one reaction section, (c) at least partially converting the supplied oxygenates in the catalyst zones under oxygenate conversion conditions into olefins and further hydrocarbons, discharging the OTO synthesis reactor product, (d) separating the OTO synthesis reactor product in a multistage workup apparatus operating by means of thermal separation processes to obtain a plurality of hydrocarbons-containing hydrocarbon product fractions, (e) discharging an olefins-containing, in particular ethylene- and/or propylene-containing, hydrocarbon product from the workup apparatus, (f) recycling at least a portion of one or more hydrocarbon product fractions to the OTO synthesis reactor as a recycle stream or recycle streams and introducing the recycle stream(s) into at least one reaction section, characterized in that all reactant mixture substreams, steam streams and recycle streams are introduced into the OTO synthesis reactor exclusively in gaseous/vaporous form and in that the oxygenates-containing reactant mixture contains dimethyl ether and is produced in an etherification reactor by catalytic dehydration of methanol in the gas phase to obtain a gaseous etherification reactor product mixture comprising DME, steam and methanol vapour, wherein the gaseous etherification reactor product mixture is sent to the OTO synthesis reactor as reactant mixture without an additional separation step. (a) providing the multistage OTO synthesis reactor having a plurality of serially connected reaction sections in fluid connection with one another comprising a first reaction section and at least one subsequent reaction section which each contain catalyst zones comprising solid catalysts that are active and selective for OTO synthesis, wherein upstream of each catalyst zone a feeding apparatus for a reactant mixture substream is arranged and wherein the last reaction section in the direction of flow is in fluid connection with a conduit for discharging an OTO synthesis reactor product, (b) introducing a reactant mixture substream into each reaction section via the respective feeding apparatus, wherein the at least one subsequent reaction section is additionally supplied with the product stream from the respective upstream reaction section, introducing at least one steam stream into at least one reaction section, introducing at least one recycle stream into at least one reaction section, (c) at least partially converting the supplied oxygenates in the catalyst zones under oxygenate conversion conditions into olefins and further hydrocarbons, discharging the OTO synthesis reactor product, (d) separating the OTO synthesis reactor product in a multistage workup apparatus operating by means of thermal separation processes to obtain a plurality of hydrocarbons-containing hydrocarbon product fractions, (e) discharging an olefins-containing, in particular ethylene- and/or propylene-containing, hydrocarbon product from the workup apparatus, (f) recycling at least a portion of one or more hydrocarbon product fractions to the OTO synthesis reactor as a recycle stream or recycle streams and introducing the recycle stream(s) into at least one reaction section,