  The general procedure for analyzing the localization of matter fields in
Brane models is by integrating, in the action, its zero mode solutions over the
extra dimensions. If this is finite, the field is said to be localized.
However, the zero mode solutions must also satisfy the Einstein equations. With
this in mind, we obtain stringent constraints on a general energy-momentum
tensor by analyzing the Einstein's equations. These {\it consistency
conditions} must be satisfied for any Braneworld model. We apply it for some
fields of the Standard Model. For a free massless scalar field, the zero-mode
localization is consistent only if the field does not depend on the extra
dimensions. About the spin $\frac{1}{2}$ field with Yukawa-like interactions,
we find a very specific relation between Yukawa function and the warp factor.
As a consequence, the spinor field localization becomes inconsistent for most
of the models studied in the literature. For the free vector field case we find
that, independent of the braneworld or the number of extra dimensions, the
zero-mode do not satisfy the consistency conditions. Finally, we consider the
mechanisms proposed to localize this field. We find that a few survive, and
even for these, the consistency conditions fix the free parameters or the
possible class of solutions allowed.
