Boris Johnson has returned to Downing Street this evening after France joined Germany in challenging him to come up with a backstop alternative within 30 days.
On his first trip abroad as Prime Minister, Mr Johnson on Thursday pressed French President Emmanuel Macron to accept his request to reopen Brexit negotiations.
Trying to exude confidence and charm in Paris, Mr Johnson called Mr Macron by his first name, spoke at times during their meeting in French and even put his foot on his coffee table.
But like German Chancellor Angela Merkel the day before, Mr Macron just smiled indulgently and appeared to dampen his expectations by saying: "We have to respect what was negotiated.
"In the coming month, we won't find a new deal that would be far away from what we have."
Mr Macron described the backstop as "indispensable", but cracked a window in saying that if Ireland could be safeguarded, some movement would be possible.
He joined Ms Merkel in raising the possibility that a negotiated departure from the EU may still be possible if the UK comes up with an alternative backstop plan, giving him a month to prove he can break the deadlock.
Ms Merkel went further on Thursday by suggesting that the idea of a 30-day deadline, which she outlined during Mr Johnson's visit to Germany on Wednesday, was a guideline.
She told reporters in the Netherlands that "it would be better to say one can achieve that by October 31."
Mr Macron said he agreed with Ms Merkel that "something clever" could be found within that period.
Speaking in Paris earlier, Mr Macron said the "two goals" the EU has with the backstop are maintaining the integrity of the EU single market and upholding the Good Friday Agreement.
He added: "The Irish backstop, as we call it, is a point that has been negotiated in the context of the geography of Ireland and the past political situation.
"So it is an important element that allows us first of all to guarantee the stability in Ireland and also the integrity of the single market. These are our two goals.
"When you talk about flexibility, well let me be very clear with you, these two goals have to be met. We, therefore, have to find a solution that guarantees the integrity of the single market.
"We have to be able to guarantee to companies, to citizens and consumers in Europe that comply with the rules of the European Union and whatever comes from a market that is not in the European Union is controlled."
Speaking after their meeting, Mr Johnson called both France and Germany "crucial friends and partners of the UK".
In a tweet, he added: "Let's get Brexit done, sensibly and pragmatically and in the interests of both sides. Let's get on with deepening and intensifying the friendship and the partnership between our nations."
Mr Macron tweeted a picture of himself talking with Mr Johnson, adding: "The relationship between the United Kingdom and France is, in my eyes, essential and unalterable.
"Boris Johnson, I see in your choice to come to Paris the need to maintain this privileged relationship. Let's work together!"
In Brussels, senior EU officials said the bloc wants to hear details of any alternative backstop plan that Mr Johnson might have and hoped that they won't have to wait 30 days for that.
Mr Johnson is seeking concessions from the EU to win support in Parliament, which has already rejected the Brexit agreement negotiated by former Prime Minister Theresa May three times.
