  The Maxwell-Chern-Simons (MCS) theory with planar boundary is considered. The
boundary is introduced according to Symanzik's basic principles of locality and
separability. A method of investigation is proposed, which, avoiding the
straight computation of correlators, is appealing for situations where the
computation of propagators, modified by the boundary, becomes quite complex.
For MCS theory, the outcome is that a unique solution exists, in the form of
chiral conserved currents, satisfying a Kac-Moody algebra, whose central charge
does not depend on the Maxwell term.
