However some analysts argued the ZEW figures were "too good to be true," with analysts at Pantheon Macro saying: "This survey is now telling an almost unbelievable recovery story for Germany and the euro zone."
"The upturn in the ZEW is unequivocal good news, but we are wary making too strong extrapolations to the real economy," the analysts added.
Meanwhile, Jennifer McKeown, senior European economist from Capital Economics, said that German optimism could be misplaced.
"Presumably any worries about the effect of the Greek crisis on the German economy were offset by expectations of ECB quantitative easing and hopes of a boost to exports from the weakening euro," she said in a note following the ZEW data.
The data suggest that the country's growth figures could pick up this year – but not by much, McKeown noted, a moot point for a country that appeared near to recession in the second half of 2014.
"For now, we expect German GDP (gross domestic product) to expand by a steady but unspectacular 1.0 percent this year and 1.5 percent next, which will do little to reduce the risk of a long bout of deflation in the euro-zone as a whole," she added.
The ZEW survey had not been a particularly reliable indicator of actual activity in the past, McKeowm stressed, adding that: "If the Greek situation deteriorates in the aftermath of this week'ends election or ECB QE disappoints, investors may well take a dimmer view of Germany's prospects."