Paris in July is quite warm and sunny, but has occasional and surprising dips in temperature. Evenings tend to be cooler. It is best to stick with layers of light, cotton clothing. Light sweaters or jackets are suitable for brisk evenings. Parisians, known for their impeccable sense of fashion, stick to natural colors and generally stay away from anything flashy. If you don’t want to stick out as a tourist, think "muted."
While men may be tempted to wear shorts and flip-flops while out about the town, it’s best to save those items for the beach. Consider light khakis or a pair of fitted jeans. Cotton T-shirts are good for the day. The Parisian men commonly wear collared shirts during the summer as well, especially with clean, casual shoes. Proper sandals also work, but it’s probably wise to leave the old sneakers at home. When in doubt, stick to a subtler, cleaner look.
The Parisian women take the opportunity in summer to wear simple, loose clothing. Dresses and skirts are particularly fashionable with nice sandals. While women do wear shorts, they’re usually for more informal occasions and not for visiting museums or dining in restaurants. Capri pants or slim khakis also work well if you’re not a fan of dresses and skirts. Bring along a few summer scarves and necklaces to accessorize. High-heel sandals are also fashionable, but are better for an evening out than a day of walking.
In July, there are sporadic rainstorms, so consider packing a small umbrella. Light raincoats or windbreakers are also useful for the cloudier, windier days. Hats are great for keeping the sun out of your eyes, but baseball caps are better left behind. Larger backpacks will make you stick out as a tourist, so take a shoulder bag or messenger bag when you’re walking around Paris. It's ideal to pack only what you need, as Paris is a hub of clothing shops and boutiques where you're sure to be tempted to buy a few Parisian items to spruce up your wardrobe.