France will on Tuesday send Britain its proposals to tackle the English Channel migrant crisis, after rejecting the UK's initial approaches as "double speak".
Prime Minister Jean Castex will write to his British counterpart Boris Johnson, with Paris signalling it is ready to discuss a post-Brexit migration deal between Britain and the EU.
Mr Johnson proposed a bilateral pact between London and Paris to return migrants to the European mainland, a move which he said would deter perilous boat crossings.
But France, which favours a UK-EU agreement, described Mr Johnson's open letter as a wrong way to negotiate and banished Britain from emergency talks on migration.
Interior Minister Gerald Darmanin said France was "ready to resume discussions with Great Britain very quickly" once there is "no more double speak and we can discuss in a serious spirit".
"Whatever our disagreements with the United Kingdom, we cannot change geography," he said. "Therefore we must get along with our British friends and allies."
Any deal with the EU "cannot be a simple agreement, as the British government sometimes says, to readmit all the migrants on European soil", Mr Darmanin said.
As well as a returns agreement, Mr Johnson called for joint patrols on France's northern beaches but French politicians have previously baulked at such as suggestion.
Mr Darmanin said the proposals by Mr Castex could include ways to open legal routes to the UK for asylum seekers and to allow unaccompanied minors to join relatives in Britain.
But he said France could not accept the practice of turning back boats at sea: “This is a red line for the French government."
Fernand Gontier, the director of France's border police, said people smugglers were launching boats from a 150-kilometre stretch of the coast.
He described an international smuggling route through which some migrants arrived via Italy and others via Belarus. Equipment was stored by traffickers in Germany before they send people on journeys to Britain.
One of the two survivors of last Wednesday's disaster, an Iraqi man, is believed to have entered the EU through Belarus, a route pushed open in recent months, before heading to northern France.
The disaster was the worst on record in the English Channel, with the loss of at least 27 lives.
The other survivor, from Somalia, claimed in an account to Iraqi media outlet Rudaw that the passengers had tried to call for help from Britain but received none.
"They said 'send us location' but we did not have time and the phones fell into the water and people started dying," Mohammed Isa Omar said. "They could hear us, we were crying for help and we called twice, not just once."
He said the boat had deflated about three hours after it left the French shoreline, before filling with water.
Mr Johnson is this week due to hold talks online with another of the key European players, Belgian Prime Minister Alexander De Croo.
Downing Street continues to insist that a returns agreement, as set out by Mr Johnson in his letter, would be the “single biggest deterrent” to migrants trying to cross the Channel.
Families of migrants who died crossing English Channel speak out
