  Double Field Theory describes the NS-NS sector of string theory and lives on
a doubled spacetime. The theory has a local gauge symmetry generated by a
generalization of the Lie derivative for doubled coordinates. For the action to
be invariant under this symmetry, a differential constraint is imposed on the
fields and gauge parameters, reducing their possible dependence in the doubled
coordinates. We perform a Scherk-Schwarz reduction of Double Field Theory,
yielding electric gaugings of half-maximal supergravity in four dimensions when
integrability conditions are assumed. The residual symmetries of the
compactified theory are mapped with the symmetries of the effective theory and
the differential constraints of Double Field Theory are compared with the
algebraic conditions on the embedding tensor. It is found that only a weaker
form of the differential constraint has to be imposed on background fields to
ensure the local gauge symmetry of the reduced action.
