Timepiece (2, 34, 62, 80) comprising a mechanical movement which comprises: - an indicator mechanism of at least one time data item, - a mechanical resonator (6, 6A) suitable for oscillating along a general oscillation axis about a neutral position corresponding to the minimum potential energy state thereof, - a maintenance device of the mechanical resonator forming therewith a mechanical oscillator which is arranged to time the running of the indicator mechanism; the timepiece further comprising a device (20, 36) for regulating the medium frequency of the mechanical oscillator, this regulation device comprising a mechanical braking device of the mechanical resonator; characterised in that the mechanical braking device (24, 38,40, 64) is arranged to be able to apply to said mechanical resonator a dissipative mechanical braking torque during periodic braking pulses which are generated at a braking frequency selected merely as a function of a set-point frequency for said mechanical oscillator and determined by an auxiliary oscillator (22, 42) associated with the regulation device, the system formed of the mechanical resonator and the mechanical braking device being configured so as to enable the mechanical braking device to be able to start said periodic braking pulses at any position of the mechanical resonator in a range of positions, along said general oscillation axis, which extends at least on a first of the two sides from the neutral position of the mechanical resonator over at least a range of amplitudes that the mechanical oscillator is liable to have on this first side for a usable operating range of this mechanical oscillator. - an indicator mechanism of at least one time data item, - a mechanical resonator (6, 6A) suitable for oscillating along a general oscillation axis about a neutral position corresponding to the minimum potential energy state thereof, - a maintenance device of the mechanical resonator forming therewith a mechanical oscillator which is arranged to time the running of the indicator mechanism; the timepiece further comprising a device (20, 36) for regulating the medium frequency of the mechanical oscillator, this regulation device comprising a mechanical braking device of the mechanical resonator; characterised in that the mechanical braking device (24, 38,40, 64) is arranged to be able to apply to said mechanical resonator a dissipative mechanical braking torque during periodic braking pulses which are generated at a braking frequency selected merely as a function of a set-point frequency for said mechanical oscillator and determined by an auxiliary oscillator (22, 42) associated with the regulation device, the system formed of the mechanical resonator and the mechanical braking device being configured so as to enable the mechanical braking device to be able to start said periodic braking pulses at any position of the mechanical resonator in a range of positions, along said general oscillation axis, which extends at least on a first of the two sides from the neutral position of the mechanical resonator over at least a range of amplitudes that the mechanical oscillator is liable to have on this first side for a usable operating range of this mechanical oscillator.