Johnson is planning meetings with French President Emmanuel Macron and German Chancellor Angela Merkel in the next few weeks, officials said Friday, as the British premier insists he will renegotiate the UK's divorce accord with the European Union.
Macron extended the invitation to Johnson in a call late Thursday from his official summer vacation residence in the south of France, where he is expected to stay for the next three weeks, said an aide.
But in a sign of wariness about Johnson's anti-EU rhetoric, France's Europe Minister Amelie de Montchalin urged Britain's new leader to create a working relationship with his partners on the continent.
"From our side, we need to be responsible," she told France 2 television. "That means being clear, predictable and it means on the other side that we need to create a working relationship, that there aren't games, posturing, provocations."
'Who will blink first?'
Macron, who has said he is happy to be considered the "bad guy" in the Brexit negotiations, is set to be a key figure during the tricky and potentially bad-tempered talks in the months ahead.
"Emmanuel Macron has had one of the firmest positions of European leaders in the negotiations," said Vivien Pertusot, a research fellow at the IFRI foreign affairs think-tank and specialist on Brexit.
"Nothing is going to force his hand and he has no reason to soften his position," he added.
Pertusot said that upcoming negotiations would be marked by "frankness" with attention on "which side is going to blink first".
Macron, a devoted Europhile who is seeking to deepen links between EU members, views Brexit as an act of self-harm by Britain and he has been highly critical of Johnson personally in the past.
The timing of the meeting between Macron and Johnson was unclear. The British prime minister is due in France to attend the G7 meeting of developed nations in Biarritz on August 24-26.
Merkel's office said Johnson had accepted an invitation from the 65-year-old German Chancellor for "an early visit" to Berlin. No date was given.
'Show we are not scared'
Johnson insists he wants to renegotiate a divorce deal which was drafted by his predecessor Theresa May over the last two years, only to see it rejected by British MPs three times in parliament.
Johnson has staked his reputation on bringing Britain out of the EU by the current October 31 deadline, meaning that if new negotiations are refused the UK would crash out without a deal in place.
The premier told Merkel said that while he would be "energetic" in seeking to reach a deal, he reaffirmed Britain must "fully prepare" to leave without a deal on October 31, his spokesman said.
Ireland's foreign minister was also quoted as saying on Friday that Johnson has deliberately set Britain on a "collision course" with the EU over Brexit negotiations.
"He seems to have made a deliberate decision to set Britain on a collision course with the European Union and with Ireland in relation to the Brexit negotiations," Simon Coveney was quoted by Irish state broadcaster RTE as saying in Belfast.
In his maiden parliamentary speech as prime minister on Thursday, Johnson promised to press ahead with plans to reopen the deal agreed with the EU.
"No deal will never be the EU's choice, but we all have to be ready for all scenarios," the European Union's chief Brexit negotiator, Michel Barnier, wrote in an email sent to EU ambassadors on Thursday.
"In this negotiation, if we want to force Boris Johnson's hand, we need to prepare for no-deal and show that we're not scared," added European diplomat, on condition of anonymity on Thursday. "He needs to know that we are ready for a no-deal."