  A new model of nonlinear electrodynamics with three parameters is suggested.
The phenomena of vacuum birefringence takes place when there is the external
constant magnetic field. We calculate the indices of refraction for two
polarizations of electromagnetic waves, parallel and perpendicular to the
magnetic induction field. From the Bir\'{e}fringence Magn\'{e}tique du Vide
(BMV) experiment one of the coefficients, $\gamma\approx 10^{-20}$ T$^{-2}$,
was estimated. The canonical, symmetrical Belinfante energy-momentum tensors
and dilatation current were obtained. The dilatation symmetry and the dual
symmetry are broken in the model considered.
