Reactors in France are shut down not because of lack of water, but as an ecological precaution because the effects of warming up rivers even more is not well known (even if it seems to have not much more impact than the heat wave in itself )
And even with these reactors shut down, France still exported 5-10GW of power at the time.
So yeah let's not propagate the anti-nuclear propaganda trying to paint the situation as "nuclear can't handle global warming and will cause blackouts", when in reality it's just us having so much decarbonated electricity that we can afford to produce less as an ecological precaution.