French President Emmanuel Macron has said he is "not sure" a UK-EU trade deal will be struck by December 31, the end of the Brexit transition period, reports BBC.
Macron said negotiations starting in March will be "tense", with fishing rights a key point of contention.
It comes as the UK government signalled it would publish its mandate for the trade deal later this week.
In the document, ministers are expected to reiterate their desire for a Canada-style deal with few tariffs on goods.
While a trade deal is hammered out with the EU, the UK is following the majority of the bloc's rules.
The UK is in this transition period until 31 December following its departure from the EU on 31 January.
