Any advance reservations to be made for Paris

Buying a Paris Museum Pass allows you to skip ticket lines. Visit the site to see what museums and monuments are covered by the pass. Buy the pass when you arrive in Paris.

I agree you want the Paris Museum Pass. If you plan on going to a fair number of museums, it's well worth it. Not only do you get to skip lines to buy tickets, but as I think Rick may have pointed out, it makes some of the more minor sights that would otherwise be overpriced worth it. You get the freedom to duck in for a short time, also to go back for repeat visits to the same museum. In May we did this at the Musee D'Orsay, visiting twice for a couple of hours on different days each rather than a single death march to try and make the most of a single admission ticket. In pure Euro terms it also saves you some money if you go to two or more included sights in a day (or Versailles). Bear in mind that some sights are open late, so if you have an active day it's easily worth it. The only catch is, it has to be on consecutive days.

I agree you want the Paris Museum Pass. If you plan on going to a fair number of museums, it's well worth it. Not only do you get to skip lines to buy tickets, but as I think Rick may have pointed out, it makes some of the more minor sights that would otherwise be overpriced worth it. You get the freedom to duck in for a short time, also to go back for repeat visits to the same museum. In May we did this at the Musee D'Orsay, visiting twice for a couple of hours on different days each rather than a single death march to try and make the most of a single admission ticket. In pure Euro terms it also saves you some money if you go to two or more included sights in a day (or Versailles). Bear in mind that some sights are open late, so if you have an active day it's easily worth it. The only catch is, it has to be on consecutive days.

You can use your Paris Museum Pass to get into the Louvre thru the Richelieu group entrance. That entrance has it's own security, so we just walked right through. It was worth the price of the Pass.

The Orsay has a separate security line for members and museum pass holders.

You can book for the Eiffel Tower in advance, but I'd advise waiting until very close to the day. If visibility is poor you won't be happy.