PARIS—French President Nicolas Sarkozy said his government would beef up spending on nuclear-safety research and development, seeking to reassure voters amid a nascent political debate over France's reliance on atomic energy.

France will invest a total of €1 billion, or roughly $1.5 billion, in nuclear technology as the government bolsters its energy industry in the wake of the nuclear crisis in Japan, Mr. Sarkozy said at a news conference Monday. The sum includes funding for a new generation of power plants and research on...