This is a global phenomenon. Real 30-year yields are steeply negative in the US as well, with nominal yield at 1.85% and year-over-year CPI above 5%.
But it helps to zoom out. This is part of a multi-decade trend in ever lower 30-year yields stretching back to the Regan administration.
https://fred.stlouisfed.org/series/DGS30
I challenge anyone to find a channel that long and that persistent (except for possibly the CPI). Keep following and you make the prediction of nominal 30-year yields touching zero within 3 years.
Somebody is on the wrong side of this trade in a big way.
Those who say the inflationary spike is temporary and will mean revert are buying bonds with wild abandon because once you break zero, you can always go deeper negative. And as yields fall, bond prices rise.
Those who say we're on the road to permanent inflation and possibly more are looking for inflation hedges. The odd thing about this is that gold, the traditional inflation hedge has gone nowhere fast.
It's also possible that both sides are wrong and what will actually happen will be unlike anything that has come before in terms of the ferocity and diversity of forces at work and ultimate pain/suffering.
For right now, both extreme sides can point to data supporting their outlook. But for how long?