SXMPMeta.DumpObject() is a debugging aid and will not print non-ASCII characters.
For your example the output of DumpObject() is:
Dumping XMPMeta object "" (0x0)
Iptc4xmpCore: http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/ (0x80000000 : schema)
Iptc4xmpCore:CreatorContactInfo (0x100 : isStruct)
Iptc4xmpCore:CiAdrExtadr = "Leo-Saurer-Stra<C3 9F>e"
Internally text is encoded in UTF-8 so here <C9 9F> is UTF-8 for Unicode U+00DF (the German sharp s).
Hope this helps,
cheers,
Jens
