Japanese buying. Toyota Pension (although it might have been Kawasaki Heavy) shifting out of US Bonds into Euro debt. So I've heard anyway.
I think it may still be from the Flight-to-Quality issue relating to the global equity sell off. Note the DAX and SMI have turned negative on the day and that reversal started about that time. Be careful of any shorts in the interest rates if the selling continues in the equities as buying in the Bund and BOBL could get feverish quite quick. Good Luck and Good Trading.