Europe's busiest train station, Paris' bustling Gare du Nord, may get a much-needed facelift after a government tribunal Friday approved part of a 600-million-euro ($663-million) plan to enlarge and modernise the 155-year-old edifice.

A noisy hive of passengers and shoppers, the station serves as a stop for the Eurostar from London, the Thalys from Belgium, Germany and the Netherlands, four suburban trainlines, and two Paris metros.

Its 35,000-odd square metres, which accommodates about 700,000 passengers every day -- growing to an estimated 800,000 by 2024 and 900,000 by 2030 -- will more than tripled to 124,000 m2 under the project proposed by national railway operator SNCF and property developer Ceetrus.

The Gare du Nord is Europe's busiest train station
The Gare du Nord is Europe's busiest train station AFP / Philippe LOPEZ

The aim is to finish the new and improved Gare du Nord in time for the 2024 Olympics in Paris.

The arrivals and departures hall will get an extra 30,000 m2, providing passengers with "space to easily move around, get their train and have sufficient space in waiting areas," according to the SNCF.

For commerce, an additional 60,000 m2 will be built, hosting among other things a concert hall and other cultural installations, a gym, shops and offices.

The upgraded station will also feature green spaces, a running track, a bicycle parking garage, and rooftop restaurants with a view of Paris' Sacre Coeur basilica, according to the plan.

The station accommodates about 700,000 passengers every day
The station accommodates about 700,000 passengers every day AFP / DOMINIQUE FAGET

The project was rejected in June by a departmental commission that evaluates commercial developments.

But on Thursday, the CNAC commission that considers appeals against decisions taken at the departmental level, overturned that ruling, and granted permission for a specific commercial aspect of the plan -- for an extension of 16,300 m2.

The go-ahead paved the way for a construction permit to be issued, but may not be the final word on the matter.

The Paris municipality, which initially backed the renovation but then withdrew its support, said Friday there must be further negotiations. It considers the proposed project to be too focused on the expansion of commercial space.

"The project, which does not meet environmental requirements, must evolve significantly to adapt to the expectations of travellers and residents," it said in a statement.

"The city wishes further negotiations and will propose alternatives as early as next week" to the SNCF and regional politicians, for "a solution that improves the comfort of travellers and the quality of life of residents."

The project has the backing of officials in the national and regional governments, however.