Prior to the construction of Charles de Gaulle Airport, Orly was the main airport of France. Even with the shift of most international traffic to Charles de Gaulle Airport, Orly remains the busiest French airport for domestic traffic and the second busiest French airport overall in terms of passenger traffic, with 28,2 million passengers in 2013.
Originally known as Villeneuve-Orly Airport, the facility was opened in the southern suburbs of Paris in 1932 as a secondary airport to Le Bourget.
Source: Wikipedia