Work is set to start next year on a 150 million euro revamp of St Malo port.
Permission has been given to replace the ageing terminal building.
The new one will be two storeys, and able to welcome 750,000 passengers a year.
Officials in the French city, visited by thousands of Channel Islanders every year, say the development is crucial to the future of port and passenger traffic there.
Work on the harbour aims to enable larger and more modern ships to dock.
The redevelopment plans were unveiled in 2022, following a three-year consultation process, and building consent was granted last week following a public inquiry.
Read: €150 Million port redevelopment proposed in St Malo
Heritage campaigners in Brittany, who are unhappy about the scale and position of the new terminal, have said they will be filing an appeal.
Artist's impression of St Malo's new Naye terminal. Credit: AREP/Myluckypixel