  We consider an effective Lagrangian describing a fluid living on
two-di\-men\-sio\-nal planes. The fluid self-interacts through a Chern-Simons
vector potential, whose field strength is proportional to the density
fluctuation. This effective Lagrangian can be related to the Anyon mean field,
but can also be considered more generally to describe a universality class of
superfluids and, when charged, of superconductors. We study the relevant
physical properties, including the spectrum, the chirality features appearing
in the polarization of scattered EM waves, and the peculiar response under a
magnetic field, i.e. a peculiar kind of anisotropic Meissner effect.
