  By using some deep tools from microlocal analysis, J. Le Rousseau and L.
Robbiano (Invent. Math., 183 (2011), 245--336) established several Carleman
estimates for parabolic operators with isotropic diffusion coefficients which
have jumps at interfaces. In this paper, we revisit the same problem but for
the general case of anisotropic diffusion coefficients. Our main tools are a
pointwise estimate for parabolic operators and a suitable chosen weight
function.
