Walking is the best way to explore and discover any city, and when it's Fashion Week the sights include tall thin young people with great bone structure in chic outfits all over the city, with an especially dense concentration around Place Vendôme. Private tents were set up in the Tuileries Garden and private security was stricter than TSA.
The throngs of tourists at the Louvre didn't seem to care that they weren't invited to the haute couture events taking place behind them. Seeing the crowds in the middle of the week in September, I can only imagine how much worse it is in the Summer, so if you are planning a visit, get a Paris Visite Pass for the day (you can also buy 2, 3, or 5 day passes) to save yourself a few hours of waiting.
There are beautiful quiet spaces between the Tuileries and the Louvre with benches and sculptures. A Paul foodtruck was parked nearby, so you can buy a sandwich or snack and have lunch before or after your museum exploration.
Walking along the Seine is a scenic way to explore the city and it helps you keep your bearings for where you are in the city, especially if you are as directionally challenged as I am :) Here you can see you are heading towards Île de la Cité because there is an island in the middle of the river.
Behind is the Eiffel Tower with the touristy Bateaux Mouches passing under a bridge. Locals still love taking the sunset cruise, so don't shy away just because it's a huge tourist attraction. There's also Batobus if you just want a waterway hop on hop off shuttle.
Eventually I walked up from the quai to street level and found myself in front of the Palais de Justice where justice has been administered for centuries. Marie Antoinette was imprisoned in a part of this huge complex before being executed. You can tour Sainte Chapelle next door, but not the administrative part of the complex.
Of course you can always opt to tour the most famous church in Paris, Notre Dame, but be forewarned that like the Louvre, the lines are tremendously long.
To give you an idea of the crowds, this is near the entry point, but the beginning of the line starts literally at the beginning of the island and snakes around like lines at Disneyland.
Even from the outside, the Cathedral is an homage to Gothic architecture from all angles.
Nearby at the Pont de l'Archevêché, the famous locks of love have taken up every possible place.
With locks locking on other locks, the idea was that people were committing their love to each other in a permanent spot. Mine would say "Elaine & Paris" :)