For a long time, the German government doubted that the real estate magnate had a genuine chance of winning the presidency, but recent opinion polls have seen the the gap between the two candidates close, with some even putting Trump ahead.
As a result, the Germans are seeking meetings with representatives from Trump's camp, to find out where he stands on important issues such as the future of NATO.
While the Brooklyn headquarters of Hillary Clinton "is constantly visited by diplomats," the establishment of relations with Trump's team is a new development, Der Spiegel revealed.
German diplomats have been holding meetings with Trump advisors including campaign co-chair Sam Clovis, who holds meetings with Berlin's ambassador to Washington, Peter Wittig, in addition to a Foreign Ministry representative.
Clovis has reiterated Trump's view that the US should pursue a less expansive foreign policy.
"Central to the attempts to learn more about Trump's true plans is the fear that, for the first time since World War II, an American president might terminate the trans-Atlantic alliance," Der Spiegel wrote.
"A Republican victory in the election could be expensive for Germany," because Trump has said that wealthy European countries cannot expect the US to spend money on their defense.
"We pay so much disproportionately more for NATO. We are getting ripped off by every country in NATO, where they pay virtually nothing, most of them. And we’re paying the majority of the costs," Trump told US television in March.
While the German government worries about the financial costs of a Trump presidency, German Chancellor Angela Merkel may not offer Trump a warm welcome after criticisms he made of her immigration policy.
Last year he said Merkel was "ruining Germany," and "blew it" when she decided to allow so many refugees into the country.
"As far as Merkel’s concerned, she ought to be ashamed of herself, what she’s done," Trump said.
I told you @TIME Magazine would never pick me as person of the year despite being the big favorite They picked person who is ruining Germany— Donald J. Trump (@realDonaldTrump) 9 декабря 2015 г.
However, the Republican candidate appeared to have had a change of heart on Friday, when he told a local reported in New Hampshire that "I think Merkel is a really great world leader."
Trump added that he still has differences with Merkel over immigration.
“I was very disappointed with the whole thing on immigration, I think it's a big problem. Really, to look at what she’s done in the last year and a half. I was always a Merkel person. I thought really fantastic. But I think she made a very tragic mistake a year and a half ago," Trump said.
According to the most recent poll by Fox News in late September, Trump is supported by 40 percent of likely voters, just three percentage points behind Democratic candidate Hillary Clinton.
In a September 14 poll in the bellwether state of Ohio, Trump was five points ahead of Clinton, 46 percent to 41 percent. Ohio, which has the seventh most electoral votes of all states, has voted for the winner of the White House in every presidential election since 1960.