We investigated the effect of huge electric field up to E=55 MV/m on tetragonal ferroelectric phase of BaTiO3 single crystal. Both lattice parameters and the dielectric susceptibility along the polar axis were determined. The induced polarization shows a continuous increase up to 20% of the spontaneous polarization. The longitudinal d(33) and transverse d(31) piezoelectric coefficients were also determined. The experimental data are described by a phenomenological approach. Interestingly, an intermediate critical electric field value of E similar to 25 MV/m was evidenced suggesting that the physics below and above this value are different