The company's own Optima Seaways, together with the chartered Visby and Kerry, will ply between Rosslare and Dunkirk six times per week in both directions.
The first departure took place at 2 pm on 2 January when Optima Seaways left the Irish seaport and arrived in France the following day at 3 pm.
Optima Seaways offers 2,115 lane metres of cargo capacity, Kerry - 2,030, and Visby - 1,800.
DFDS has prepared COVID-19-safe cabins for truck drivers for the duration of the crossing.
"The route offers exporters and transport companies direct and paperless lorry transport between Ireland and other EU countries, reduced costs and less waiting time and the opportunity to avoid the customs procedures that now apply to transport via the UK land bridge," the company stated in a press release.
To this Aidan Coffey, DFDS, Route Director, added, "As well as offering a vital alternative to the UK land bridge for Irish industry, Dunkirk represents a key strategic location, with easy access to the Paris region, and close to the French-Belgian border and onward access to the Netherlands and Germany."
He also said, "We are extremely pleased with the great interest we are experiencing from customers on both sides of the route. This means that the departures are already fully booked. I also want to express a big thank you to Rosslare Europort and the Port of Dunkirk for their great cooperation and support that has helped us get ready for operation in a very short time."