Commuters can now access the internet between the RER C stations Bibliotheque François Mitterrand in the south east of the city and Saint-Ouen to the north.
That means in theory, they should be able to browse the internet whilst travelling through 18km of tunnels under the city.
France's national rail company SNCF has said it will help to guarantee “better information and more responsiveness” in the event of any travel disruptions as users can now follow the RER C Twitter account in real time and receive notifications from the mobile application.
Meanwhile, the capital's transport network RATP is working on launching 4G across the whole of the Metro by 2019 despite passengers initially being promised that they would be able to access the internet across the network by the end of 2017.
At the moment, passengers on the Metro can access the internet at just 120 stations with the date for full access pushed back due to technical issues.