From my experience, Italians and in the south of France. The French also shut everything down on Sundays.

In the middle east I’ve also seen people napping in mosques. The large ones remain nice and cool during the hot summer day. Mind you, it was Ramadan, so that might have changed things.

Overall, I expect people in hot climates to sleep through the mid day heat and go back to work later. I for one envy them.