  We describe all fusion subcategories of the representation category of a
twisted quantum double of a finite group. In view of the fact that every
group-theoretical braided fusion category can be embedded into a representation
category of a twisted quantum double of a finite group, this gives a complete
description of all group-theoretical braided fusion categories. We describe the
lattice and give formulas for some invariants of the fusion subcategories of
representation category of a twisted quantum double of a finite group. We also
give a characterization of group-theoretical braided fusion categories as
equivariantizations of pointed categories.
