  We study the dynamics of classical and quantum systems linearly interacting
with a classical environment represented by an infinite set of harmonic
oscillators. The environment induces a dynamical localization of the quantum
state into a generalized coherent state for which the $\hbar \to 0$ limit
always exists and reproduces the classical motion. We describe the consequences
of this localization on the behavior of a macroscopic system by considering the
example of a Schroedinger cat.
