My first trips to Paris were podiatric disasters. Shoes I'd proudly worn ten years disintegrated as I realized how sedentary Cleveland life was. Turns out, pillows made of marshmallow clouds and rainbows hurt after walking here to Chateau-Rouge in them. Figuring out what shoes worked best in the city took a lot of trial and error, limping around the flat, and wasted money, but now it's down to a science and will hopefully spare you harried shopping trips and hallux abducto valgus deformities. Note: These tips are for leather shoes. Sorry not sorry, I don't have any synthetics. Leather breathes, keeps feet cool, and softens with every wear. After a few uses, leather soles have great traction.
Brush a small amount of beeswax and a few drops of lanolin, jojoba, or olive oil onto shoes to make them water and stain repellent. Olive oil is often shredded by internet trolls, but leather experts recommend it. It's an ingredient in many shoe creams and won't breed mold when used properly. Buff with a soft, lint-free cloth (like a flour sack towel).
Cleaning and deodorizing leather and suede
White vinegar removes salt stains, dirt, and grime from all types of shoes. Use one part water and one part white vinegar to discourage mold. To restore suede, apply vinegar-water solution using a natural bristle brush (any clean scrubber will do). Gently brush suede in various directions to scrub dirt from fibers. Use a piece of bread or art gum eraser to remove stains. Wipe insoles lightly with white vinegar and dry (preferably in the sun) to deodorize. Alternately, leave orange peels, clove buds, or baking soda in shoes overnight.
Breaking in new shoes
Paris shops heat-stretch their own shoes (even secondhand pairs) for free. Rub beeswax around the insides to soften and lessen their bite. It sounds counterintuitive, but stockings and low-cut socks enhance comfort and prevent blisters. I wear Swedish Stockings; one French option is Cervin, which are plastic-free but not vegan- 100% silk, produced in Sumène, readily available secondhand in Paris (they boil the worms). During colder months, I wear no-show socks over stockings. They keep feet dry and are invisible in heels.
Maintain your investment
After a month of use, a competent cobbler can attach half-soles and rubber toe pads without ruining the original leather. I like Cordonnerie des Belles Feuilles. Resole shoes when necessary, before they wear out. Polish with beeswax and sweet almond oil- according to Brian Atwood, "You just want the protection and to bring the luster back; you don’t want polish to add any color. It’s like moisturizing your skin.”
Store shoes in dust bags in their original boxes. Some boxes come with polaroids stuck on them, which is demeaning. If you need a photo to remind you what's inside, you have too many shoes. Plastic shoe trees and boxes encourage mildew and mold; unvarnished cedar shoe trees absorb moisture and prevent leather from cracking. The prettiest are 36€ at BHV (BHV is the worst, but cordonneries tend to carry ugly, expensive embauchoirs). For shoes worth over $200, get the kind with ventilation slots and brass knobs. For shoes worth over $700, use lasted shoe trees.