Summer clothes for women in Paris

If you don't want to look like an American tourist, choose slacks with hems closer to the ankle, more like a crop pant than a capri. Sandals are fine if they are not athletic-style like the Keens and Tevas I wear when kayaking.
I avoid wearing white on vacation as it easily shows dirt/spots.
Tee shirts are also fine but European women tend to choose natural fabrics, not the polyester/athletic styles popular in the US.
The most important consideration for clothing and sandals/shoes is comfort. It is more important than fear of looking like a tourist and wanting to blend in with the locals.
It is your vacation to enjoy.

3 brutal truths:

Not all Parisian women dress the same

Nobody cares what you wear

Whatever you wear people will still know you are an American tourist

So wear what you like (subject of course to requirements in places of worship, for example) and enjoy yourself.

No matter where I am I like to wear skirts that reach the knee in warmer weather. I feel more cool and I can coordinate with any slacks I bring to make more outfits. I dress in Paris as I do elsewhere in Europe. However, it does drive my daughter crazy as she wants me to dress more chic when there. I keep telling her that's a lost cause. Comfort is my main concern these days.

An earlier reply about always being identified as an American brought back an amusing incident that my family still fondly remembers and laughs about.
My brother-in-law and I were admiring a painting at the National Gallery in London. My sister, across the gallery, was approached by 4 Brits asking for directions to the John Constable paintings. When my sister responded with her American accent "Let me look at my map", the Brits apologized profusely saying they thought she was an employee of the museum.

I am an American, born in the mid-west farming region. I have been approached numerous times by Italians in Rome & Florence, & by French people in Paris, thinking I was a local and asking for directions. I have no Ittalian or French ancestors.

Also - sadly, sometimes restaurant and shop owners do care very much how you dress. You may get preferable service and better seating.

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I have travelled to Europe in April, May, June, September and October and I live on the northern Gulf Coast - all HOT and at home we endure a miserable amount of humidity. I find loose fitting dresses to be the best alternative to surviving the heat. I have several dresses from Tommy Bahama and Fresh Produce that are great for travel and hot weather. The dresses are not thick or heavy but they are not so thin that I need a slip.

While I love shoes, for me they are now limited. I have plantar fasciitis and tarsal tunnel syndrome (think of it as carpal tunnel syndrome in your foot), so I am essentially restricted to tennis shoes with orthotics. I wear them gratefully because without them I would be in constant pain and unable to do the things I want to do. Also, I try to buy basic color shoes (cream, black, dark blue) without reflective detailing. I have traveled and dined in several European cities including Paris in said tennis shoes with nice dresses (or pants) and no one (noticeably) raised an eyebrow.

I agree with pj on the longer (crop) pants and Quince has some great options.

As everyone else has said, Parisians will know you are a tourist anyway. You will encounter more negativity for failing to greet or respond to a greeting (remember bonjour, bonsoir and your basic words of courtesy) than if you wear tennis shoes.

A lightweight silk scarf always looks classy in Paris and can dress up almost any outfit.

In reply to several of comments received:

I have vacationed in Paris ten times, always when the temperature ranged from about 50 to no more than 65 degrees—which I consider ideal. Temperatures in the mid-70s indicate summer weather to me, which is too warm for me.

I dress in Paris as I do at home in New York—appropriately and comfortably. I am not concerned about looking like “a tourist.” The tips about ankle length pants are helpful.

Mid to late September is still a month away. It’s impossible to predict what the temperatures will be like then. It could very well be that the temperatures are in the 60 to 65 degrees range, especially in the mornings and evenings.

Wear shoes or sandals you can walk on pavement in for hours. So sandals, probably athletic soles. There are lots of shoes with great athletic soles that are also decent enough looking.

It is easier to deal with shoes if you wear pants; I have lightweight boho rayon pants I wear in heat -- cool and at my age, my leg doesn't need to be on display. And thus I can wear whatever shoes are comfortable.

When I was younger I wore skirts and that is by far the coolest choice -- it doesn't mean a bit more care about shoes.

ultimately -- comfort first.

There are plenty of photos and “live” reports online on what Parisian women are wearing. Here is a recent one: https://styleparis.substack.com/p/paris-street-report-09-what-parisians

And some Instagram videos:

https://www.instagram.com/reel/DcROGU4tVeO/

https://www.instagram.com/p/DMEiDjnu2DT/

https://www.instagram.com/p/DXpYdEejuA8/

https://www.instagram.com/p/DYub63HhIxk/

Thank you, Mary from Massachusetts! This was the most helpful response I received.