We start on Sunday. Imm guessing there wint be much open on Sunday afternoon or evening in France. So I take it the controls have food.
General note: in France Mondays are as bad as Sundays - both days morning is OK but shops close midday and don't re-open. Of course normal rules
may not apply in PBP week / on PBP route.
But it's OK to rely entirely on controls for food, unless you have special needs. Especially as you're going to be ahead of the bulge, usual warnings about queues don't apply so much, at least on the way out.