When it became clear that May would become the next prime minister of the UK, some in Germany voiced cautious optimism that she would seek to limit the damage inflicted by British public's vote to leave the EU.
The fact that she was in the Remain camp and bears a passing resemblance to the sober and pragmatic Chancellor Angela Merkel raised hopes that she would build bridges with Germany.
But her appointment of Boris Johnson, the charismatic but erratic leader of the Brexit campaign, has shaken this belief.
Speaking to DPA, Ralf Stegner, deputy leader of the Social Democratic Party (SPD) said “Frau May comes across as weaker due to her choice of cabinet.”
Johnson doesn't appear to be a great diplomat, Stegner observed: “And now he's negotiating the Brexit. Safe travels!”
The appointment also met with harsh criticism from the Institute for the World Economy (IfW), one of Germany's leading economic think tanks.
“How can May speak of national unity in her inaugural speech and then appoint the man who split the land as her foreign minister,” asks IfW president Dennis Snower in a written statement.
“One can only hope that other politicians in Europe recognize how dangerous, almost crazy, it is to integrate populist deceitful politicians into government.”
A writer for Der Spiegel magazine, the bastion of the liberal establishment, described Johnson scathingly as “a snake oil salesman” and a “reckless con artist” who had led a “campaign of deception”.
“The appointment is sensational, at first sight it comes across as crazy.”
But the liberal magazine journalist explains the appointment as a clever ploy on the part of May to scapegoat the former mayor of London.
“Johnson has to clean away the debris that he himself offloaded in front of 10 Downing Street… May brought those responsible for Brexit out from behind the bushes they were hiding behind and stuck them in the front row.”
Conservative Die Welt also sees the choice of Johnson as having more than meets they eye, suggesting May wants to be entertained by watching Johnson's buffoonery play out on the biggest stage of all.
The new prime minister has constrained Johnson's power by creating two new posts that concern foreign issues - a minister responsible for Brexit negotiations and a minister for international trade - Die Welt notes.
“His job will be limited to what he does best - charming people. As foreign minister he will play a similar role to the one he played as mayor of London, only on a bigger stage. And why should May deny herself this show, this unique talent to advertise for Britain?"
But in a sign that it doesn't mean its analysis altogether seriously, the paper also describes Johnson as an “undiplomatic, unpredictable disloyal jack of all trades."
Sylke Tempel, editor of Internationale Politik and Berlin Policy Journal, points out that Johnson's appointment is more significant than just a power game within the conservative elite, and can only spell bad news.
“FM Boris Johnson aka the Irresponsible [one] who caused the mess, won't make cleaning up his mess any easier,” wrote Tempel on Twitter.
Munich daily Süddeutsche Zeitung has given up hope that the British establishment take anything seriously any more: “Johnson as foreign minister? That is British humour" its headline reads.