Paris' three airports are failing to improve services to travellers who too often wait in queues and pay high prices at duty-free boutiques, a report by a French auditing body said on July 9.

The managing company of Charles de Gaulle international airport, Orly and Le Bourget air terminals was criticised by the Cour des comptes for increasing airport tax without in turn offering better services to passengers.

"The quality of services remains insufficient at Paris airports despite some improvements," said the report.

Travellers struggle to find their way in the terminals, little information is given to them and waiting queues are poorly managed, it said.

The report also noted that goods on sale in airport boutiques as well as meals and drinks in bars and restaurants were high-priced.

Passport controls at the airports are poorly managed during peak times as are bus transfers to planes, added the report.

Aeroports de Paris (ADP), which manages the three airports, was partly privatised in 2006, but the French state remains the majority shareholder.

The company plans to pour EUR2.7 billion (US$4.3 billion) into airport modernisation until 2010 and increase its capacity to accommodate an additional 20 million travellers.

The report noted that the problems were not all ADP's fault.

Some of the older terminals at Charles de Gaulle airport were built without toilets, "which turned out to be unsustainable," it said.

The Cour des comptes recommended that ADP keep closer watch over its sub-contractors who operate at the airports.