We experimentally demonstrate that atomic orbital parity mix interferences can be temporally controlled on an attosecond time scale. Electron wave-packets are formed by ionizing argon gas with a comb of odd and even high-order harmonics, in the presence of a weak infrared field (IR). Consequently, a mix of energy-degenerate even and odd parity states is fed in the continuum by one-and two-photon transitions. These interfere, leading to an asymmetric electron emission along the polarization

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... r. The direction of the emission can be controlled by varying the time delay between the comb and IR pulses. We show that such asymmetric emission provides information on the relative phase of consecutive odd and even order harmonics in the attosecond pulse train.