Its is always the way that this scenario happens; you have been on charter pretty much continuously for the last 3 months, your next drop off is on 14th of August and the next pick up is on the 16th of August. You are knackered so take the rest of the 14th off to relax. So it is off early Monday the 15th of August to provision, right?
Having not had much contact with the outside world, you don't realise that the 15th of August is a public holiday in France. Stepping out with your shopping bags, credit card in hand, catching the taxi to the nearest supermarket, only to be greeted by an automatic door that will just not open!!
In France most of the shops will close on pubic holidays except for smaller shops and bakeries who will open for a couple of hours in the morning with the exception of Christmas Day where all shops will be closed.
Ask locals or other chefs what the deal is in your area, personally in the above scenario I would make alternative plan to get my provisions early to make sure I had them on board so less stress.
Carrefour Supermarket France hours are normally
8.30 am - 9pm Monday - Wednesday
8.30 am - 10 pm Thursday to Saturday
Consider these hours where Monday is the public holiday.