What’s the deal with the Rentree this year?

Paris has been deserted until today, the last day before school officially starts. In other years, we noticed an increasing activity each day leading up to school day. This year though, things are different. Several hypotheses:
1. Many people without kids still have this week off and are Still lazing on the beach somewhere.
2. Those with kids did indeed come back, but are laying low, depressed about the end of the summer. They are sleeping in and only coming out after lunch.

What’s the story? Does anyone know?