In his speech opening the "Grand Paris" for the 21st century exhibition, President Sarkozy promised a ten year programme, starting in 2010 or 2011, to improve rail links between Paris and its two airports. He offered €21bn for the "Big Eight": a 130 kilometres (80 miles), driverless, 24-hour metro system in the form of two large loops, joining across the centre of the city.

The northern loop would have a branch to Charles de Gaulle airport. The southern loop would link the centre of the city to, amongst other places, Orly Airport and Versailles.