"The scenario that is becoming the most likely is one of no deal," said the official, who asked not to be named.
Boris Johnson is due to meet Emmanuel Macron in Paris on Thursday for a working lunch. Photo: AFP
The official, speaking on condition of anonymity, rejected Johnson's demand that the so-called "backstop" mechanism to avoid border checks between Ireland and Northern Ireland be scrapped.
And he also contradicted Johnson's claim that if Britain leaves the EU without a deal it would not have to pay a €43 billion divorce bill that has already been negotiated.
"The scenario that is becoming the most likely is one of no deal," the official said ahead of the first meeting between Macron and Johnson since the British premier took office a month ago.
"The idea of saying 'there's not a deal, so I won't pay' does not work," the official said.
"We cannot imagine that a country like the UK would back out of an international commitment."
The official added: "There's no magic wand that makes this bill disappear."
The French official said that a letter sent by Johnson to EU Council President Donald Tusk on Monday asking for what he called the "anti-democratic" backstop to be withdrawn "posed a problem" for the whole EU.
The backstop is a mechanism to avoid border checks between EU member Ireland and Northern Ireland, part of the UK, with checkpoints there removed as part of a 1998 peace deal on the divided island.
German Chancellor Angela Merkel warned Wednesday of the economic impact of a chaotic no-deal Brexit, hours before she was to receive Johnson on his first foreign visit.
The current Brexit day is October 31st and Britain's new Prime Minister Boris Johnson has repeatedly said that the UK will be leaving on that date, with or without a deal.
Brexit has previously been scheduled for March 29th and April 12th, but was postponed as previous Prime Minister Theresa May attempted to get British MPs to back the Withdrawal Agreement she had negotiated with the EU, but with no success.
The official added that France did not expect Johnson to seek an extension to the October 31st deadline, but the EU would be ready to grant one in case there were new elections called.
And he dismissed any notion that there were differences between Macron and Merkel on the issue of Brexit, which he said would cause economic harm to the EU and Britain, but mostly for Britain.
"There is not the width of cigarette paper between Paris and Berlin on these issues," he said.