@mametsuko @fristi it's because the reason it gets hot (at least in french houses) is because the walls are built to hold heat, so they absorb heat and then slowly release it
the walls actually get HOTTER than the ambient air, because they're exposed to the sun, and will literally dump this extra heat inside
even with the windows open and the shutters closed and air circulation, it doesn't help because the walls are essentially natural radiators
in most cases (up to about 30C outside temp) it is hotter inside than out