Process for the regeneration of an at least partially coked molecular sieve catalyst comprising introducing the at least partially coked catalyst into a regenerator; introducing into the regenerator an oxygen-containing gas to regenerate at least part of the at least partially coked catalyst, thereby producing a gaseous mixture and at least partially regenerated catalyst; separating at least partially regenerated catalyst and at least part of the gaseous mixture; and analyzing the composition of the gaseous mixture to control the burning rate of the coke present on the at least partially coked catalyst in the regenerator by adjusting the mass flow rate of the oxygen-containing gas on the basis of the analysis of the gaseous mixture.