Germany's consumer price index fell 0.3% month-over-month in January.
It's the first time the inflation rate went negative since September 2009.
"Deflation has arrived," Pantheon Macroeconomics' Claus Vistesen said.
Deflation is a very scary phenomenon. When prices fall, consumers and businesses often hold back on purchases hoping for even lower prices. Economic activity seizes and prices continue to fall in a self-reinforcing cycle.
Germany's negative CPI number was largely due to the ongoing plunge in energy prices, which were down 9.9% year-over-year.
But other price are slowing or dropping, too.
"The decline in food prices also accelerated to -1.3% in January from -1.2% in December," Vistesen noted. "Services inflation fell to 1.2% from 1.4% last month and rents declined to 1.3% year-over-year from 1.4% last month."
Pantheon Macroeconomics