Time zones from Firebird 4 are handled by FbZonedDateTime and FbZonedTime types respectively. Given the lack of proper support for time zones in .NET (especially cross platform), these types provide the building blocks for developer to work with time zones using some library (i.e. NodaTime). Both FbZonedDateTime and FbZonedTime can be used as parameter value for FbParameter.
Examples can be found in FbTimeZonesSupportTests.