  We give a Lagrangian and display all local symmetries for N=4 topological
string by Berkovits, Vafa and Siegel, the latter previously known in the
superconformal gauge. Leading to a small N=4 superconformal algebra and
exhibiting the manifest Lorentz invariance the model is proposed to be a
framework for restoring the manifest Lorentz invariance in N=2 string
scattering amplitudes.
