In the context of ecological change and the fight to reduce CO2 emissions, nuclear energy can appear to be an efficient energy source, or at least essential from the perspective of energy diversification. However, it suffers from a poor image and a lack of knowledge among the population, and among young people in particular, who favor the development of renewable energy. We wanted to know exactly what was happening in one of the most nuclearized countries in the world, France. To do this, we interviewed a young, student, "non-expert" population about their knowledge and perceptions of nuclear risk and compared the results with a so-called "expert" population: firefighters, most of whom had received training in radiation protection. Thus, in response to the question "Are you afraid of the nuclear sector?" 68% of students answered yes compared to 49% of firefighters. The reasons for fear are sometimes similar (radioactive waste, contamination over long periods, ageing of power plants), and sometimes divergent due to the better knowledge of the firefighters who had undergone radiological training (out of control, fear of the effects of radioactivity). Science students differed from other students by being more in favor of a partial exit from nuclear power (50%, compared to 12% for students from other disciplines), and by indicating that they were more open than others to the possibility of changing their minds if they had more knowledge on the subject (43%). In terms of behavior, the gaps are, as expected, wide between the 2 populations (students/firefighters): less than half (44%) of students adopt the right reflexes (seeking a confined space, sealing ventilation), 55% would prepare for an evacuation and 84% would keep themselves informed, not through social networks as we might think, but through a state organization in charge of managing the nuclear sector. If an alert were to occur, students report that they would be anxious (42%), frightened (12%) or even panicked (25%), unlike firefighters who would of course behave as expected, be more reasoned, and much less panicked (difference of 21%), although half of them admit that they would still be anxious. The results reveal differentiated profiles between the 2 populations (expert/non-expert) in terms of the association between exposure to radioactivity and the occurrence of cancers, and in the level of confidence in nuclear energy in France.