On 13 July 2011 the European Commission opened three in-depth state aid investigations regarding the Marseille and Frankfurt Hahn airports and an investigation into lower taxes for air passengers in Ireland for domestic flights. The Commission is investigating support received by Marseille airport between 2005 and 2007 for its low-cost airline terminal and fee reductions awarded to low-cost carriers and incumbent airlines. The Commission has expressed doubts over whether the investment was proportionate to the objectives and concerns that the fee reductions may have provided a selective advantage to certain airlines. In Germany, the Commission is looking into credit lines, loan refinancing and guarantees given to Frankfurt-Hahn airport by publicly-owned institutions which appear to contribute only to the operating costs of the airport. Ireland’s tax scheme levied on departing customers at differential rates for domestic and international passengers, operating between March 2009 and March 2011, is also under investigation. Under the Commission’s 2005 Aviation Guidelines, Member States can provide financing to regional airports handling up to five million passengers per year and to airlines wishing to start new routes from these airports. However, such projects still have to be scrutinised under the state aid rules.