The Destatis office estimated that sales were either unchanged or decreased by up to 0.5 percent from 2007, based on figures for the 11 months from January to November.
In nominal terms, which consider only the actual numbers recorded, retail sales were forecast to have risen by 1.9-2.4 percent, a statement said.
For November, adjusted data showed a monthly increase of 0.7 percent from October, when sales had plunged by 2.2 percent from the previous month.
The one-month increase in November exceeded a forecast by analysts polled by Dow Jones Newswires, which saw sales gaining 0.5 percent in adjusted terms.
On a 12-month basis however, they lost 3.0 percent in November.
Consumption is traditionally the weakest link in Germany's export-oriented economy, and officials regularly seek to boost consumer spending, especially since exports have been curbed by slowdowns or recessions in major global economies.