July and August are the two summer holiday months in France. Most people go away for 3 weeks, some a lot longer. Wives will go away for about 2 months with the children. Especially if they have a house in the countryside, by the sea, or relatives in the countryside... It was a Sunday, so even the husbands will have joined their families in the holiday homes.
The peak holiday time is 1st three weeks of August when it's, usually, the hottest and driest. So that's why the villages look empty.
What surprised me was the lack of tourists. I went for lunch at a popular restaurant and the restaurant was only half full. I noticed that the cafes and restaurants were also only about half full.