However, France is refusing to meet Mr Johnson’s conditions and has demanded the new Tory leader soften his position. Mme de Montchalin told the public broadcaster France 2: “We want to work with the new prime minister. And above all, we need to. The UK is a partner which will still be a partner after Brexit. It’s a country that will stay very close to us. But in diplomacy, if we have absolute red lines, they often create tensions.”
She added that while the October 31 deadline was not set in stone, Britain would need “a very, very good reason to push back the divorce date”.
France wants to “get past the stage” of negotiating the Brexit deal with Mr Johnson and begin “calmly” mapping out Britain’s future relationship with Brussels, France’s EU chief said, stressing the current withdrawal agreement was not up for renegotiation.
She said: “We have always said that if the United Kingdom wants to leave the European Union in an orderly manner, the accord is the best solution we have.”
Mme de Montchalin added the withdrawal deal agreed by Mr Johnson’s predecessor Theresa May last year was the result of two years of hard work between London and Brussels.
The deal, she insisted, lays out “point by point, pragmatically and realistically, how there can be a before and an after” Brexit.
“With this accord, we are saying: ‘this is how we are going to break up’,” she added.
“We have to create a working relationship and not get into games, gestures and provocations,” Mme de Montchalin warned, in a thinly veiled reference to Mr Johnson’s threat to pull the UK out of the EU with or without a divorce deal.
Her comments came shortly after French President Emmanuel Macron invited Mr Johnson to Paris during a phone conversation on Thursday to congratulate him on becoming Prime Minister.
M Macron has adopted a tough stance on Brexit, and is one of the EU leaders most determined to see Britain leave the bloc in October, without a deal if it chooses, so as to preserve EU stability and unity.
But Brexit talks are currently stuck, with both London and Brussels refusing to make further concessions to break the deadlock.
Mr Johnson warned the EU bloc on Saturday the “anti-democratic” Irish backstop had to be dropped if they were to strike a divorce deal, a demand that has angered Ireland and irked other EU capitals.
“If we get rid of the backstop, whole and entire, then we are making a lot of progress,” the new PM said when asked if it was only the Irish border backstop that he wanted changed.
The backstop is an insurance policy designed to prevent the return of a hard border between Ireland and the province of Northern Ireland by provisionally keeping the UK in a customs union with the EU.
But many lawmakers oppose the idea of being chained to EU rules and customs duties that would prevent Britain from striking its own trade deals and leave it overseen by EU judges.
European leaders, for their part, are prepared to rewrite the non-binding political declaration on future EU-UK ties, but have insisted they will not reopen the withdrawal agreement.
Mr Johnson hopes that the threat of the economic chaos that a no-deal Brexit would trigger will convince EU leaders to revise the divorce deal, but they have so far proved immune to his demands.