I respectfully disagree on that. It"s on the contrary a decision made a few months before the elections - so that the French energy policy won't be a matter of debate on the voting day.
French citizens have never been put in a position to vote between a pronuclear candidate and an antinuclear one.
Well, of course, there are ecologists on the first round of the vote, but on the second rounds, both candidates are always pronuclear. Of course, they all started ten years to include electoral promises to balance the energy mix with more renewables but none delivered: France has recently been recognized as being at the worst country in the European Union with only 19% of renewables in our mix - despite having signed to reach 23% this year.
The left is deeply divided on the matter ; in fact, the left is divided on all ecological issues: agriculture, industry, energy ... The right is pro-big-polluting agriculture in the name of our commercial deficit (we export a.lot), anti-regulation of industry on ecological grounds because our industry is weak (which is true but not a reason), and pronuclear in the name of sovereignty - on the energy issue but also for military reasons. The fact that the nuclear energy enables France to emit far less CO2 is just a welcome argument. But if we had petrol like Norway, it would be "drill, baby, drill !".
The nuclear energy has nothing to do historically in France with ecology and the climate issue will reinforce that totally nondemocratic decision taken by the General De Gaulle in the name of our Grandeur. A policy that our technostructure follows without any true democratic supervision. Check and balances exist only on safety matters, but absolutely none of the French energy mix.
Nowadays it has become a political subject of course. But it's really just theater and will stay so for quite a while. The public opinion had been leaning on the right more and more for the last 20 years. When elected, self-called Socialists acted clearly on a center-right: really more like Manchin than Biden (in a daring transposition of very different political landscapes).
Funny detail: the French scientists had stalled in the research of the atomic bomb. That was a problem for the US in the context of the Cold War. So the US told the British to tip us in the right direction. That direction had already been deeply worked on but dismissed by the French scientists.
That was very discrete, not even officially recognized by some secret treaty. A prominent English nuclear scientist had a good friend among the French team. He visited him for lunch a Sunday. They talked physics. The UK has already its bomb, so the French noticed when his friend wondered aloud if that path come be "another way" to reach fission. But the British moved on another subject immediately. Friends don't need many words.
To thank the US, France later helped Israel - a lot - to build their own atomic bomb faster.
Then France made a 180º turn in its foreign policy and sided with the Arab countries on the Israël/Palestine issue. When Arafat and his troops were besieged in Beyruth by Tsahal, France evacuated them to Tunisia.