The German 30 year bond is yielding 2.8%:
bloomberg.com
The US 30 year bond is yielding the same:
Yahoo Finance
There is no margin of safety in Germany debt against the strong likelihood that the country will be forced (by Merkel and other banker tools) to absorb the losses of the rest of Europe.
Of course, there is no margin in safety in US bonds either at this price, certainly not enough to compensate for the probability of trillion dollar deficits forever. I expect yields to stay low through this cyclical bear market, but not much beyond that. Bonds will continue to be a good short at times when they are overbought, and we may be approaching such a time.