Calendar mechanism for chronograph watch

A calendar mechanism for a chronograph-watch, said watch including a motor module, a chronograph module disposed over and linked with the motor module, and a dial indicating elements disposed over said chronograph module, said motor module comprising, a first date ring arranged so as to be stepwise driven one step per day by means of a mechanism controlled by a motor element borne by the motor module and a correcting mechanism for manual correction of the position of said first ring, and the chronograph module including a second data ring located immediately under the dial and bearing indications concerning the date which indications appear through an opening formed in the dial, said second ring being controlled by the first ring through a drive chain assembled in said chronograph module.