Alas, the five-week long winter sales extravaganza is now over, but you can always find great deals (and, if you’re persistent, great shoes) along the Rue Meslay in the 3rd.
This street, just off the Place de la République, is lined with shoe wholesalers, most of them open to the public. About half of them have exactly the same selection of very tacky shoes that seem to have arrived from China (shipped in the 80s), selling for as little as €10. The other half are a mix of last season’s or current season’s shoes at cheaper prices than you’d find in department stores.
Some very random designer shoes can be found at Dina Brice (#13), and I know I got these shoes in one of the first three shops on the left (as you head west along the street), but I was on a shoe high and can’t recall which one. You could spend a couple of hours trawling this street, but it’s a good idea to do a general reconnaissance mission before making any purchases so that you get a good idea of the price range and quality — all which vary.