A process of controlling the thickness profile of a blown tubular film, consisting of thermoplastic plastics, around the circumference of same when producing blown film by means of blown film extruders, having a film extrusion die, wherein a measuring device measures the film thickness of the tubular film around the circumference and wherein a control device variably controls the cooling gas flow as a function of the measured film thicknesses around the circumference in sectors, wherein cooling gas flows are supplied from the outside in the direction of production in two separate planes, and wherein the cooling gas flows are controlled variably and in circumferential sectors around the circumference in the two planes in respect of their physical parameters.