© Agence France-Presse/Getty ImagesAir France planes are parked on the tarmac at Charles de Gaulle-Roissy airport, outside Paris, where flights were cancelled due to the heavy snowfall.
Around 2,000 people were evacuated from Paris Charles de Gaulle airport because of snow on the roof of a terminal.

People remained calm during the evacuation of the terminal - described as a precautionary measure taken because of around two feet of accumulated snow on the roof.

Emergency workers were deployed to clear the roof, a task expected to last until around 14.00 GMT, the source said.

A few weeks after the terminal was opened in 2004, a section of the roof of the architecturally-ambitious building designed by Frenchman Paul Andreu collapsed, killing four foreign travellers and injuring six others.

French aviation authorities had announced earlier on Friday morning the cancellation of half of all flights into and out of Charles-de-Gaulle airport until 1:00 pm (midday UK) because of freezing winter conditions.

The flight cancellation meant that some 2,000 passengers were forced to stay overnight at the airport on Thursday, Transport Minister Nathalie Kosciusko-Morizet said.

Forecasters were expecting below-freezing conditions and the airport was having trouble getting hold of enough glycol, the liquid used to de-ice aircraft, aviation officials said in a statement.

Civil aviation officials had therefore asked all airlines to reduce their flights by 50 percent, the statement added.

Aeroports de Paris (ADP), the company running the capital's airports, announced earlier on Thursday that airlines had already been asked to cut flights by 20 percent, delaying 60 flights out of Roissy.

The de-icing process had been taking 25 minutes instead of the usual 14, because of the conditions, said ADP.

Charles de Gaulle airport had only just cleared the backlog from the delays caused earlier in the week by the freezing conditions, which on Monday saw 3,000 passengers forced to spend a second night sleeping there.

The delays earlier this week led to angry exchanges and scuffles with police as frustrated passengers complained not just about the delays but the lack of information from the airlines.