We investigate the thermodynamic conditions under which an isotropic dipolar hard sphere fluid freezes into an unpolarized or ferroelectric crystalline state by minimizing a free-energy functional. This functional is based on the direct correlation function of the isotropic fluid, calculated by reference hypernetted chain integral equations. In the framework of our approach, the ferroelectric fluid phase, found in simulations, is surpassed by a ferroelectric body-centered tetragonal crystal.