  We propose an extension of the Fokker-Planck model of the Boltzmann equation
to get a correct Prandtl number in the Compressible Navier-Stokes asymptotics.
This is obtained by replacing the diffusion coefficient (which is the
equilibrium temperature) by a non diagonal temperature tensor, like the
Ellipsoidal-Statistical model (ES) is obtained from the Bathnagar-Gross-Krook
model (BGK) of the Boltzmann equation. Our model is proved to satisfy the
properties of conservation and a H-theorem. A Chapman-Enskog analysis and two
numerical tests show that a correct Prandtl number of 2/3 can be obtained.
