Here a graph that shows "total energy used in the country minus its production of energy", which shows that France that mostly produces nuclear energy consistently requires more energy than it produces.
https://www.theglobaleconomy.com/france/Energy_imports/
Even though that wasn't really what I am talking about. The reality is that France frequently has to shut down many of their reactors, which causes them to for longer periods of time require energy from Germany.
The reason for that is that for example in July 2022, 29 of their 56 nuclear plants were offline due to outages. Given that as you the majority of what France produces is nuclear energy, this is a big problems. These offline plants still require energy for cooling. So if other countries didn't provide energy France would have had a blackout.
This is not to be pro-gas or coal. This is to say that just everyone switching to to nuclear energy isn't a magical fix.
In 2021, France exported a total of some 87 terawatt hours of electricity. Meanwhile, electricity imports to France amounted to 44 terawatt-hours that year
Ukraine war turned France into a net importer (not by much) but their situation is far from as bad as in other countries, for example my country, Italy.
energy production by source in France
https://en.wikipedia.org/wiki/Energy_in_France#/media/File:F...
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energy consumption by source (the mix is much more diversified than the production)
https://en.wikipedia.org/wiki/Energy_in_France#/media/File:E...
It's true that they had to shutdown multiple reactors, but on average their energy production creates a surplus respect to their demand.
France is one of the biggest exporters of electricity in the World and that's where most of the non-nuclear and non-renewable production goes.