Reservations are needed for the Louvre, but you can still expect a long queue to enter. Before you buy your ticket and make a reservation, be aware that certain sections of the Louvre are closed on certain days of the week. For example, the exhibit of French Impressionists is closed on Mondays.
The good news: my wife’s cane got us to the front of the line without even asking.. The bad news: our favorite exhibit was closed today. But we still enjoyed ourselves. C’est la vie.