Turbofan having a longitudinal axis and comprising a motor and a nacelle, surrounding the motor, which comprises a fan casing, in which a duct for a bypass flow is delimited between the nacelle and the motor and in which a flow of air flows in a flow direction, said nacelle comprising: - a fixed structure fixed to the fan casing, - a mobile assembly having a mobile cowl and a slider, the mobile cowl being fixed to the slider, the slider being mobile in translation, on the fixed structure, in a direction of translation between an advanced position in which the slider is positioned such that the mobile cowl is moved close to the fan casing and a retracted position in which the slider is positioned such that the mobile cowl is moved away from the fan casing so as to define, between them, an open window between the duct and the exterior of the nacelle, - a plurality of blades, each one comprising a first end mounted so as to be mobile in rotation on the slider about an axis of rotation, and where the blades are angularly offset from one to the next about the longitudinal axis, wherein each blade is mobile between a stowed position in which the blade is outside the duct and a deployed position in which the blade is across the duct, - an assembly of actuators causing the slider to move between the advanced position and the retracted position, and vice versa, and - a manoeuvring system intended to move each blade from the stowed position to the deployed position and vice versa, where the manoeuvring system comprises: - for each blade, a shaft mounted so as to be mobile in rotation on the slider about an axis of rotation, and on which the blade is fixed, - for each blade, a toothed sector that is fixed to the shaft and is coaxial with the axis of rotation, - a toothed arc that is coaxial with the longitudinal axis, mounted so as to be mobile in rotation on the slider about the longitudinal axis, where the teeth of the toothed arc mesh with the teeth of each toothed sector, - a cam as one with the toothed arc, and - a groove, as one with the fixed structure, which receives the cam and where, when the mobile assembly moves, the cam follows the groove and rotates the toothed arc. - a fixed structure fixed to the fan casing, - a mobile assembly having a mobile cowl and a slider, the mobile cowl being fixed to the slider, the slider being mobile in translation, on the fixed structure, in a direction of translation between an advanced position in which the slider is positioned such that the mobile cowl is moved close to the fan casing and a retracted position in which the slider is positioned such that the mobile cowl is moved away from the fan casing so as to define, between them, an open window between the duct and the exterior of the nacelle, - a plurality of blades, each one comprising a first end mounted so as to be mobile in rotation on the slider about an axis of rotation, and where the blades are angularly offset from one to the next about the longitudinal axis, wherein each blade is mobile between a stowed position in which the blade is outside the duct and a deployed position in which the blade is across the duct, - an assembly of actuators causing the slider to move between the advanced position and the retracted position, and vice versa, and - a manoeuvring system intended to move each blade from the stowed position to the deployed position and vice versa, where the manoeuvring system comprises: - for each blade, a shaft mounted so as to be mobile in rotation on the slider about an axis of rotation, and on which the blade is fixed, - for each blade, a toothed sector that is fixed to the shaft and is coaxial with the axis of rotation, - a toothed arc that is coaxial with the longitudinal axis, mounted so as to be mobile in rotation on the slider about the longitudinal axis, where the teeth of the toothed arc mesh with the teeth of each toothed sector, - a cam as one with the toothed arc, and - a groove, as one with the fixed structure, which receives the cam and where, when the mobile assembly moves, the cam follows the groove and rotates the toothed arc.