The French ambassador to the US tweeted “a world is collapsing before our eyes" as the results of the country's presidential election were becoming apparent and Donald Trump's dreams of winning the White House became a reality.
Gerard Araud, an experienced diplomat who is expected to work with the next president, later appeared to delete the tweet.
The 63-year-old said in French: “After Brexit and this election, everything is now possible. A world is collapsing before our eyes. Dizziness.”
His response comes as French President Francois Hollande responded to the election result, saying it heralded an era of "uncertainty".
"I congratulate him as is natural between two democratic heads of state," he told reporters.
"This American election opens a period of uncertainty. This context calls for a united Europe, capable of making itself heard and of promoting policies wherever its interests or values are challenged."
Mr Hollande, who has not yet announced whether he will run for a second term in next year's French presidential election, said Paris wanted to immediately commence talks with Trump to clarify his position on key international issues.
French Foreign Minister Jean-Marc Ayrault agreed to work with Trump, but said the Republican's election "raised questions".
"Europe cannot blink after Brexit, after the election of Donald Trump with all the questions being raised," he told France 2 Television.
"Europe must stand together more, be more active and go more on the offensive even if it is just to protect itself."
Europe's far-right leaders in Europe greeted the election result with delight, with the president of France's Front National, Marine Le Pen, among the first to offer their congratulations.
Other European leaders offered more muted congratulations to the Republican following his shock win.
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