Athens officials launched Thursday a "Grand promenade" to link monuments and archeological sites via a pedestrian walk and bicycle paths.
Automobile and scooter congestion in the centre of the city would be eased as 6.8 kilometres (4.25 miles) of streets are reserved for foot traffic and cycling.
Shop owners are concerned, however, about the impact that work on the project will have on their business, which was already harmed by a lockdown aimed at battling the coronavirus epidemic.
"The Grand promenade is a large-scale works project to radically change Athens' historic centre," the mayor's office said in a statement.
The coronavirus crisis added momentum to the operation, which is to be completed in 2022, it added.
Work is to begin near the national parliament with the installation of cycling paths and wider pavements, before extending to other parts of the city centre over the summer.
During the final phase, the promenade is to link up with an already existing five-kilometre (three-mile) tree-lined walk around the Acropolis that was created for the 2004 Olympic Games.
Automobiles are to be banned from the city-centre zone while the work, which includes the installation of charging stations for electric vehicles and additional green spaces, is carried out.
Drivers who violate the ban face fines of 150 euros ($170), the city said.
"The city centre is opening up to everyone, not just cars as is the case still today," Mayor Kostas Bakoyannis said as he launched work on the project.
He added that it would put an end to scooters on the pavements, create new public spaces and allow buses to circulate more quickly.