Consumer prices, harmonised with inflation data from other European Union countries (HICP), rose 1.0% year-on-year after an increase of 1.1% in July, the Federal Statistics Office said.
The August reading undershot a Reuters forecast for 1.2%, was the lowest level since November 2016, and marked a fourth month running well below the ECB's target of close to but below 2% for the euro zone as a whole.
Separate German Labour Office data showed seasonally adjusted unemployment rose 4,000 on the month in August, eroding a pillar of growth that has helped support an economy whose traditionally powerful export engine is sputtering and that could well slip into recession in the current quarter.
With its sales abroad hit by a worsening trade climate, a global economic slowdown and an increasingly chaotic run-up to Brexit, the bulk of Germany's growth momentum is been generated domestically - a dependency that leaves it exposed to any weakening of the jobs market. Thursday's German inflation data will have done nothing to water down those expectations.
On the month, EU-harmonised prices fell by 0.1% after an increase of 0.4% in July. The market had expected an unchanged reading. The national inflation figure (CPI) eased to 1.4% year-on-year from 1.7%, mainly due to a slower rise in energy prices.