Following a complaint by a low-cost airline, the European Commission (Commission) conducted an investigation into differentiation in passenger charges in France between domestic flights and flights to/from countries within the Schengen area. The Commission took the view that the cost difference gave an advantage to airlines operating domestic flights in France, affecting competition and trade between Member States, and therefore constituted State aid. In 2008, France abolished the differentiation for all airports other than those in Paris. On 28 January 2009, the Commission accepted an offer by France to abolish differences in rates for Paris airports by 1 April 2009.