What kind of stores are you looking for? I'm not much of a shopper, but I don't think of the Latin quarter as a shopping area, unless you are talking about boulangerie, patisserie, etc. I do like the convenience of the Latin Quarter as well as the vibe of the area. I was in Paris and staying in the Latin Quarter on a Monday and found plenty to do. If you have the Paris Museum Pass, it's pretty convenient for a check of attraction days/hours to determine what is open. On one of the Mondays I was in Paris, I went to the Arch de Triomphe and then walked the Champs de Elysees. Those stores were all open, though except to pick up some leggings at H & M, I didn't go into any of them. I walked all the way to the Touilleries and found it to be a lovely walk.