PARIS — Torrential rains have caused deadly flooding in central and northeastern France this week, forcing the evacuation of thousands of people, some on boats or kayaks, and threatening works of art stored in Paris’s most celebrated museums.

A man on horseback was swept away by floodwaters on Thursday and found dead in Évry-Grégy-sur-Yerre, 30 miles southeast of Paris, the authorities in the Seine-et-Marne administrative department, where the town is located, said. In Germany, heavy rains claimed the lives of nine people.

The heavy rains caused the Seine in Paris to rise to 18 feet by Thursday evening, flooding the lower embankments and shutting several roads but causing no significant damage. The level is still far from the record of 1910, however, when the river rose to 26 feet.