Ok so this is the way shopping goes (in explanation of why and what shops are closed on Mondays)
The supermarket is open Mondays.
The bakery with the good multigrain bread is not.
The bakery up the street with the good 'tradition' baguette is.
The butcher and the primeur (produce: veg & fruits) are closed.
The bank is not open on Monday, but it is open part of the day on Saturday.
And the post office is open Saturday half day, not Sunday, but yes on Monday. (And the post office is also a bank).
Totally clear, right?
You could make tacos on Sunday except the only place to get real cheddar is at the supermarket. So instead you could make soup, but the bakery with the good baguettes is not open so you'll have to settle for multigrain.
But the flower shop is open every day.