There's some info on this at the BMI:-
http://www.bmi.bund.de/cln_006/nn_163598/I..._94317__de.htmlAs I have found these links seem to change a lot, I have attached what I thought were the useful documents on this topic. (I think it is jolly decent of the German government to provide this stuff in English!)
From the Immagration Act Summary:-
"In order to implement the freedom of movement within the European Union, residence permits will be abolished for EU citizens. In future, EU citizens will merely be required to register with the registration authorities, in the same manner as Germans. EU citizens are to receive certification confirming their right of residence (EU Act on the General Freedom of Movement for EU Citizens, Section 5)."
...and from the Zuwanderungsgesetz document, Article 2 Section 8:-
"
Obligation to carry identification papersEU citizens and their dependents shall be obliged,
1. on entering the Federal territory,
a) to carry a passport or a recognised passport substitute on their person and,
b) on request, to hand over such identification papers to a competent official for
inspection,
2. to hold the necessary passport or passport substitute for the duration of their stay
in the Federal territory,
3. to present the passport or passport substitute and the certificate confirming the
right of residence under Community law and the EU residence permit to the
authorities charged with implementing this Act and to hand over the aforesaid
papers and leave them with the said authorities for a temporary period, should
this be necessary in order to enforce or safeguard measures under this Act."
The tricky thing is that not all the behoerde seem to have heard of these changes. When I was last at the Auslaenderbehorde, some Czech woman was being bounced between there and some other Amt, being told to get an Aufenthaltserlaubnis by one lot and being told she didn't need one by the other lot.
P.S. I couldn't attach the Zuwanderungsgesetz document - I think it was too big. It should be on the website of the BMI or the Auswertiges Amt.