Brittany Ferries is suing DFDS, claiming unfair competition on the Newhaven-Dieppe route.
The French firm says it has launched the legal challenge this week over grants received by its Danish rivals from the Normandy region - claiming it has cost BF £125 million in lost business since 2013.
Guernsey's ferry operator has begun the action in France, with a court date set for 6 June in Brest. It has also complained to the EU's competition watchdog, the EU Directorate-General for Competition.
In an interview with the French newspaper Le Marin, Brittany Ferries' company president Jean-Marc Roué said: "Subsidies granted by the Syndicat mixte transmanche (SMPAT) in Normandie allow DFDS to levy artificially low fares that are out of touch with economic reality.
“This draws a significant proportion of freight and passenger traffic to the Newhaven-Dieppe route, to the detriment of Brittany Ferries.”
Pas d'autres commentaires que les faits, et rien que les faits ! https://t.co/fA7ACSDCO5
— Jean-Marc Roué (@jmrouebferries) May 21, 2025
Earlier this year, Brittiany Ferries lost a legal challenge against the Jersey government's decision to award the island's ferry contract to DFDS.
Read: Brittany Ferries' legal challenge of Jersey contract denied
In April, the Court of Appeal ordered BF pay DFDS £40,000 in legal costs.

Commonwealth Games: Nowacki into 100m breaststroke final
Channel Islands face 'physical' Poland test
Thousands expected at Havre Des Pas Festival this weekend
Price of heating oil and other fuel increase by more than half in a year
Man jailed for importing nearly £600k worth of cannabis in bumpers of his car
Baby born on Guernsey's Marine Ambulance
Drug trafficker who claimed he was the ‘Accredited Dealer' jailed
Jersey men involved in cocaine importation sentenced