I will second that recommendation to check for AC. We did 10 days in the south of France late June/early July staying with family (no AC) and 2 of those days in Paris (no AC) - it was 110 degrees in Paris and 90’s daily on the coast. We basically lived by the pool or sea when we weren’t doing touristy stuff. Paris was pretty horrible!
The one thing I will recommend is the train system for traveling within the country. Very comfortable, AC! and fast and really pretty affordable.