Nuclear is the most expensive form of energy on the market. If you fast forward two decades, countries will be producing power at vastly different cost levels that will dictate their economic success. Those relying on nuclear will be piling on debt for getting power way above market prices.

Germany never had a substantial nuclear deployment. It peaked around 20GW. About 8 remains. The disappearance of 16GW from the grid was a complete non event. No blackouts. No instability. It just happened gradually and now its gone. The remaining 8 are tiny compared to daily fluctuations in wind and solar that are also not an issue. In terms of base load it is completely irrelevant whether it stays or goes. It's certainly not worth paying a lot for. If you replace 20GW with a few hundred GW of wind and solar, you end up with plenty of capacity and baseload. That's more or less what happened in the last few decades. The French already import excess power from Germany and elsewhere below the price they are selling their own nuclear power quite often.

Nuclear never mattered in Germany other than for military strategic reasons that stopped being relevant when Russia withdrew their tanks from the DDR 30 years ago. All that remains is cold war era obsolete plants that are expensive to keep going. Shutting them down was going to happen no matter what (because they are obsolete and near end of life) and the decision to not build replacement plants was pretty much a constant. The debate around that was pretty much over before Fukushima already. All that did was fast track some of the decision making. It remains a popular and uncontroversial decision in Germany.

Macron is announcing intentions and plans in the middle of an election season where Macron is under a lot of pressure from right wing populist parties. This nuclear push is very much motivated by nationalist sentiments and Macron is in damage control mode as he's losing voters to several right wing parties; some of which you might classify as far right or even neo fascist.

We'll see what remains of those intentions and plans after the elections. Election time posturing is not to be confused with actually policy to spend many billions on nuclear. Assuming he actually wins, he might find himself once more forming a government with a few other parties that will have strong opinions on this topic and not a lot of budget to allocate to a wide range of topics competing for attention. Until that government is a reality, all you have is a politician trying to stay in power trying to appeal to voters currently entertaining the thought to vote for someone else. Even with these announcements, we're still talking a net decline in nuclear capacity over time. It's just slowing it down slightly.

Personally, I think it is wise for the French to keep the knowledge to build reactors going for another generation. Additionally, exporting that knowledge to e.g. the UK is good for their economy. Hinkley Point C is being built by French EDF. Of course, there are plenty of scandals surrounding that particular setup related to cost overruns, delays, etc. That seems to be a constant with nuclear. One thing is certain, it won't be cheap power. Gas is cheaper, even with the recent price increases. Saving money is not a reason to go nuclear. It never was. Whether the UK ends up buying more is very much up in the air. The drama around Hinkley Point C is probably not helping the nuclear case currently. And having to send the money to France is probably not helping that case.