Is there a way to obtain, if possible on-line, the individual accounts
of a company in Germany ?
I am specificaly seeking the individual accounts of T-Mobile Deutschland
GmbH, based in Bonn.
In some European countries you can buy this kind of information
on-line (for instance in Belgium: Banque Nationale de Belgique /
Centrale des Bilans).

As far as I know (and I am German) such information is considered
confidential according to German law.

Scriptor

Lieber Herr Scriptor,
I am surprised!  The financial figures of a German corporation (AG =
Aktiengesellschaft and GmbH = Gesellschaft mit beschränkter Haftung)
are deposited with the Registeramt and anyone can inspect them.  This
also applies for branches of foreign banks and on limited level of
disclosure for a KG = Kommanditgesellschaft.  A GmbH the size of
T-Mobile has the same disclosure requirement as an AG.  Whether the
data is available online, I do not know, nor whether you can pay to
have the registeramt (registry office) copy it for you.
In principle, this is a similar system to that in England with Companies House.

Here is one site for t-mobile that has some preliminary figures for
2004.  The final audited figures would not be complete at this time: 
http://www.t-mobile.de/downloads/pressemitteilungen/05-03-03_unternehmenszahlen_2004.pdf

Maybe with this info you or an eager web-expert can find more.