President Nicolas Sarkozy on Tuesday repeated his call for France to keep nuclear power, accusing the political left of stalling progress by campaigning to reduce reliance on atomic energy.

"It saddens me to hear more and more speeches questioning the very idea of progress, including in domains that until now were uncontested in our country, that were subject to political consensus between left and right," Sarkozy said.

"It's a serious matter because it suggests calling into question an entire industry, as well as hundreds of thousands of jobs," Sarkozy said during a visit to a space centre in the southern city of Toulouse.

France's opposition Socialists and Greens last week agreed a deal to jointly campaign for France to reduce its reliance on nuclear energy from more than 75 percent to 50 percent by shutting 24 nuclear reactors by 2025.

The Greens say that alternative energy sources like wind and solar power would compensate for the effects on the economy of abandoning atomic power.

France is the world's most nuclear-dependent country, operating 58 reactors, and has been a leading international proponent of atomic energy.