Updated

Flash floods in southwestern France claimed two elderly victims in the space of 24 hours as unseasonal storms caused havoc across huge swaths of the country on Wednesday.

Flights into Paris were disrupted as the French capital sweltered in conditions more akin to Hong Kong at this time of year and the flooded Catholic pilgrimage site of Lourdes was closed to visitors for a second day.

A woman in her 70s was swept away overnight by the floodwaters after getting out of her submerged car at Saint Beat near Lourdes, the local prefecture said in a statement.

She and her husband had been evacuated from their home but were heading back to collect personal effects when they were trapped by the water. Her husband was rescued by firefighters.

That tragedy was followed on Wednesday afternoon by the death of a 75-year-old man, who was also swept to his death after the floodwaters at Luz-Saint-Sauveur in the Pyrenees turned a local stream into a torrent.

The region has been lashed by storms since Tuesday and more than 2,000 people have had to be evacuated from their homes, some of them by helicopter.

The impact of the storms, which have followed an exceptionally wet spring across much of France, was underlined when a bridge at Saint-Laurent-de-Neste was washed away by a tributary of the Garonne river.

Northern France was also hit by severe weather conditions on Wednesday with an electrical storm forcing the suspension of takeoffs and landings at Orly airport in Paris for 20 minutes in late afternoon.

"Three flights had to be diverted to (the other Paris airport) Roissy-Charles de Gaulle," a spokesman said, adding that further disruption was likely later in the evening.

"It rained like we were in the tropics," said Gerard Millet, the mayor of the small town of Melun, just outside Paris. "We've got 30 centimetres (a foot) of water in some of our streets."

The hot and humid conditions made life very sticky for Paris commuters, but they did have one positive impact with France's cherry farmers finally being able to harvest their first ripe fruit of the season, three weeks later than is normal.

Six students at Montauban de Luchon in the Haut Garonne had to sit their baccalaureat exams in the town's thermal baths because of concerns that their college, where they board, could be flooded.

That meant an overnight stay at the baths between two papers, and Bryan, one of the students, told AFP: "It was a bit unusual, but at least I will always remember doing my bac!"

The shrine at Lourdes, where the Virgin Mary reportedly appeared to a peasant girl in 1858 and whose water many believe has curative powers, remained closed on Wednesday.

Tourists in the town were relocated from their hotels to higher ground as the Pau river burst its banks in a rerun of what happened last year, when flooding caused hundreds of thousands of euros in damage.

Lourdes attracts millions of visitors every year. The Catholic Church recognises 68 miracles linked to it and many disabled or sick people go there to pray for a cure.