Boris Johnson is to meet Emmanuel Macron later, hours after the French president insisted reopening negotiations is "not an option".
Mr Macron said: "We have to help the British deal with this internal democratic crisis but we mustn't be hostage to it nor export it."
On Wednesday, German Chancellor Angela Merkel said the onus was on the UK to find a workable plan.
Mr Johnson said a deal could be achieved with "sufficient patience".
BBC
Russia's unmanned Luna-25 spacecraft has crashed into the Moon after spinning out of control, officials say.
Donald Trump has confirmed that he will not take part in Republican presidential debates with his rivals in the race for the White House.