By Michel Rose

French lawmakers have urged their government to stay firm over fishing in Brexit negotiations, potentially making it harder for EU negotiator Michel Barnier to reach a compromise with Britain.

In a report approved by the National Assembly's European affairs committee on Thursday, lawmakers urged President Emmanuel Macron's government to fight to keep French fishermen's right to work in British waters.

"The (European) Union must continue to guarantee that fishing won't be sacrificed to save other sectors," the report seen by Reuters says. It was co-written by Jean-Pierre Pont, a member of parliament for Macron's party who represents the town of Boulogne on the English Channel, France's busiest fishing port.

Fishing is shaping up to be one of the main sticking points in the Brexit transition negotiations.

Britain wants to become an "independent coastal state" after a transition ends this year, arguing it should have yearly negotiations to set fishing quotas with the EU as Norway does. London also does not want any agreement on fisheries to be linked to a free trade deal.

EU diplomats had told Reuters last month the bloc was willing to shift its stance on fisheries and move from the "maximalist position" of maintaining the existing situation to help forge a trade deal with Britain.

But any French refusal to budge could make it harder for Barnier, who negotiates on behalf of the EU's 27 members.

"The government must stay as firm as possible," Pont told Reuters. "Britain can't be better off outside than inside."

The increased pressure on Macron comes after his foreign minister, Jean-Yves Le Drian, who is from the coastal region of Brittany, warned he was determined to defend access to British waters.

The lawmakers also urged Paris to do more to prepare for a no-deal, which they said was the "most likely scenario".

British fishing grounds are among the richest in the North East Atlantic zone where most of the EU catch is hauled in.

(Reporting by Michel Rose; Editing by Andrew Heavens)