On the local symmetries of gravity and supergravity models

We present here a detailed analysis of the local symmetries of supergravity in an arbitrary dimension D, both in the component and superfield approaches, using a field-space democracy point of view. As an application, we discuss briefly how a complete description of the local gauge symmetries clarifies the properties of the supergravity-superbrane coupled system in the standard background superfield approximation for supergravity.