  We compare results of the exact field theory of phase separation in two
dimensions with Monte Carlo simulations for the $q$-state Potts model with
boundary conditions producing an interfacial region separating two pure phases.
We confirm in particular the theoretical predictions that below critical
temperature the surplus of non-boundary colors appears in drops along a single
interface, while for $q>4$ at critical temperature there is formation of two
interfaces enclosing a macroscopic disordered layer. These qualitatively
different structures of the interfacial region can be discriminated through a
measurement at a single point for different system sizes.
