France seized on Thursday a British trawler fishing in its territorial waters without a licence and issued a verbal warning to a second vessel, amid a bitter row between the neighbours over access to fishing grounds after Brexit.
French maritime minister Annick Girardin said on Twitter that the trawler was rerouted to the port of Le Havre under a maritime police escort.
France is furious that Britain has refused to grant its fishermen the full number of licences to operate inside British water that Paris says is warranted, and on Wednesday announced retaliatory measures that could come into effect from Nov 2 if no progress is made in talks, reports Reuters.
Those measures include additional customs checks on goods entering the European continent through France's border and prohibiting British fishing boats from unloading in several French ports, the French government said.
Britain has said it has issued fishing licenses to vessels that have been able to demonstrate a track record of operating in its waters in the years running up to its withdrawal from the European Union on Jan 31, 2020.
Negotiations between Britain and the European Commission over the affair have continued this week.
Patience in Paris has worn thin over what French officials call Britain's failure to honour its word since Brexit, overfishing and also Britain's demand to renegotiate the Northern Ireland protocol aimed at maintaining the integrity of the EU single market.
French maritime gendarmes conducted multiple checks on fishing vessels off Le Havre, northern France, overnight, Girardin's ministry said, as France intensifies its surveillance during the negotiations.