Hi OH! In August there are almost no any people in Paris, just only the tourists, especially is the employees who go to their vacations, even the business people .It is calm and with some of people who stay in Paris, me too, sometimes I go to pass my vacations at the beach or travel abroad. So August is a month of holiday here in France.
I'm french and I don't do anything special. Mind you, when I was living in Quebec, there were certain unions where workers all took time off for two weeks. So instead of being short handed throughout the year due to a few employees being on holidays, they will shut down the whole plant instead. That way, production is not affected during regular operations. Perhaps in France, there are special celebrations that we do not celebrate in North America. I know that in Canada, only in Quebec do they get St. Jean Baptist day as holiday, whileas rest of country it is not a statutory holiday as it is there.
They probably do the same thing from September through July