As France boosts security in the wake of Friday night's deadly Paris attacks, airlines are being warned they will be fined if they fail to ensure that passengers entering the country have valid identity papers.

The notice, which also comes ahead of international talks on climate control that will bring world leaders and thousands of foreign officials to Paris in the coming weeks, was issued by the pan-European air traffic agency Eurocontrol on Saturday.

It applies whether or not passengers travel from inside the so-called Schengen area in Europe, where border checks between 22 signatory countries have been largely scrapped since the 1980s.

Failure to comply with the rules could lead to fines of 5,000 euros per passenger, Eurocontrol's statement said.

Hours before the attacks, in which at least 127 people were killed on Friday night, France announced it was restoring long-abandoned intra-Europe border controls for a month to boost security for the climate summit, which runs from Nov. 30 to Dec. 11.

While Interior Minister Bernard Cazeneuve spoke about the clampdown before Friday's killings, the extra restrictions come as security has been heightened after the string of attacks in Paris, for which the militant group Islamic State claimed responsibility.

At Vienna airport, a Reuters reporter on a delayed Saturday night flight to Paris said a special announcement informed passengers that they must have a valid passport or identity card.

Among passengers on the Austrian Airlines plane was a group of Chinese tourists heading to the French capital on the last leg of a Europe tour, some of them sanguine but others worried.

"We are coming because it is booked by the company. I would have liked to go somewhere else today," said 29-year old Feng. "I am worried we won't be able to do anything because of what happened and I'm scared for the safety."

Another passenger, 57, who declined to give her name, said she didn't fully understand what was happening in France, but still wanted to go there.

"It scares, but Paris is where we all wanted to go," she said.

Another passenger who took an internal flight to the capital on Saturday from the French island of Corsica off the southeast mainland coast said small groups of armed soldiers were doing the rounds, but identity checks were no tougher than normal.

"The soldiers were patrolling in groups of four or five with pretty impressive guns but, beyond that, the checks did not seem more than usual, though this was an internal flight," Sylvie Chaineau, who landed at Orly airport south of Paris, told Reuters. – Reuters