Elaine Sciolino has a new book coming out about the Louvre, which she admits to first hating and now loving. She also wrote a book about the Rue des Martyrs and was once a NYT columnist.
https://www.amazon.com/Adventures-Louvre-Worlds-Greatest-Museum/dp/1324021403
It's excerpted in the newest issue of Travel & Leisure (Selma Blair on the cover). Don't want to give away too much for copyright reasons but, she outlines her preferred two hour tour. It's pretty complicated, with lots of to'ing and fro'ing and U turns but it might be of interest. Perhaps find the magazine.
My favorite piece of her advice is to show up with a full stomach and empty bladder.