PARIS/LONGJUMEAU, France (Reuters) - Torrential rain forced thousands of people from their homes south of Paris while the River Seine surged to its highest level for over 30 years in the French capital, shutting down the famed Louvre and Orsay museums and a metro line.

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In Evry-Gregy-sur-Yerre, south of Paris, a man on horseback drowned on Thursday, the prefecture said in a statement. Le Parisien newspaper said the 74-year-old had been trying to cross a flooded field. The horse survived with minor injuries.

He was the second victim of the torrential rains that have caused the Loire and Seine rivers to burst their banks. An 86-year-old woman was found dead in her flooded house in a small town southwest of Paris late on Wednesday.

“Since yesterday it’s just been a deluge,” said Jerome Coiffier, an inhabitant of Longjumeau, less than 20 km (13 miles) south of Paris, where firemen wading thigh-deep in water rescued inhabitants using inflatable boats.

At least 3,000 out of 13,000 inhabitants were evacuated in Nemours, 75 km (45 miles) south of Paris, as floodwaters crept towards the second story of buildings in the town centre.

Prolonged heavy rain also pounded parts of neighbouring Germany and at least five people have died in floods in Bavaria state in the south of the country, officials said.

In Paris, the Seine rose above 5 metres (16 feet), forcing the SNCF rail operator to close the RER C commuter line that runs along the river and is used by tourists to reach the Eiffel Tower, Notre-Dame Cathedral and Versailles.

The Louvre museum shut down and said it would remain closed on Friday to keep its priceless art safe. The Orsay museum of Impressionist art will also be shut on Friday. Both are located right by the Seine in central Paris.

The Seine could peak at six metres in Paris on Friday, officials said, stressing that this was still well below the level where it would pose danger to residents. The river reached a record high of 8.6 metres in 1910, when thousands of Parisians had to flee flooded low-lying areas of the city.

President Francois Hollande declared a state of emergency in the worst affected areas and promised funding to help local authorities deal with flood damage. Unusually heavy rains in June showed the urgency to curb climate change, he said.

In the Loire Valley, Chambord castle, a UNESCO world heritage site, found itself surrounded by water.

The national weather service said the greater Paris region had in May endured its wettest month since 1960.

In the Loiret region, where local officials called on the army to help evacuate motorists trapped on the A10 motorway, the floods were the most severe in a century.