We classify the unitary representations of the extended Poincar\'e
supergroups in three dimensions. Irreducible unitary representations of any
spin can appear, which correspond to supersymmetric anyons. Our results also
show that all irreducible unitary representations necessarily have physical
momenta. This is in sharp contrast to the ordinary Poincar\'e group in three
dimensions, that admits in addition irreducible unitary representations with
non-physical momenta, which are discarded on physical grounds.Comment: 7 pages; commentaries added in Sect. IV A and in Conclusion; added
reference