Price growth stood at 1.4 percent year-on-year, federal statistics authority Destatis said in preliminary figures, some 0.6 percentage points lower than in April.
Most of the items like food, energy and goods that feed into the inflation index saw relatively stable price growth compared with last month.
But services inflation plummeted, from 2.1 percent in April to just 1.2 percent in May.
Analysts had last month noted that higher April inflation was mostly due to a late Easter pushing up prices for package holidays.
Price growth data for individual states like Hesse and Bavaria showed a massive slump in prices for all-inclusive trips this month.
April's 2.0-percent inflation reading had marked a rare moment of inflation being bang on the European Central Bank's target for industrial powerhouse Germany.
Despite years of ultra-low interest rates and 2.6 trillion in stimulus, the Frankfurt institution has struggled to meet its price stability target of inflation close to, but below 2.0 percent across the 19-nation eurozone.
Price growth was just 1.3 percent in Germany in May when measured using the Harmonised Index of Consumer Prices, the ECB's preferred yardstick.