Thousands of people filled the streets of five French cities Saturday to protest plans to build the next generation of nuclear reactors - fuel-efficient but seen by anti-nuclear activists as a re-launching of France's nuclear energy program. Organizers put the number of protesters in the western city of Rennes at 30,000 to 40,000 - a figure that could not be officially confirmed. The collective Get out of Nuclear put the number in Lyon and Toulouse at 10,000 and claimed another 5,000 protesters in Lille, in the north, as well as in the eastern city of Strasbourg. The simultaneous protests organized by the collective, made up of hundreds of associations, was a way to get the issue in the eye of candidates in the April-May two-round presidential elections. Only the Greens party, whose candidate is Dominique Voynet, is resolutely opposed to the third-generation European pressurized-water reactor, or EPR, technology that aims to use 17 percent less fuel.