What to buy in advance for our trip to Paris?

The only thing I would bother buying in advance is access to the Eiffel Tower. Everything else can be bought there without a hassle and for les smoney.

http://www.toureiffel.paris/en/preparing-your-visit/buying-your-tickets.html

I agree you should buy your Eiffel Tower tickets online before hand. I'm not sure how quickly they sell out for April, but when I bought ours they were sold out in a matter of minutes. Remember the time difference when you buy them. I stayed up until midnight and had my website all set up to just click the mouse and buy them. I made a mistake, had to redo it, and by then (1 minute) the time slot I wanted was gone! I bought them the first day they went on sale at the time they went on sale. We did get another time slot and it was well worth not waiting in line. We went in July, so it might be different in April. But, just keep an eye on the web sight and you can see how fast they are selling out.

One thing to consider - purchasing the Paris Museum Pass. It gets you into tons of museums and sites and will get you to the front of the line for many of them. I buy one each time I go to Paris and get a lot of value out of it. It does allow you to skip the line at the Louvre. It also gets in into Versailles. http://www.parismuseumpass.com

I would buy the Versailles tickets (and print them out) before you go, including reserving a tour. The tour is well worth it as you see some unique rooms and skip the lines. Book through their official site. http://en.chateauversailles.fr/homepage

The Paris Museum Pass could be very useful. Decide in advance if you want it, but wait until you get there to buy it. It's sold in lots of places - most sights that accept it, the TI kiosks (there's one in the square in front of Notre Dame) and some department stores too.

If you want to take a tour in Versailles, you may need to book that in advance.

We can give you tips for individual sights and organizing your days, once you have chosen what you want to see. One place to start is the Paris Museum Pass website, where you can get information on all the sights that are included in the pass.

Yes, you should definitely try to buy advanced tickets for the Eiffel Tower and Versailles. The Paris Museum Pass, which you shouldn't buy in advance, allows you to skip the ticket-buying lines at numerous sites all across Paris. This allows you to poke your head into a place that tickles your fancy as you're walking past and it also gives you access to the toilets at all of those sites, no small matter when you're walking around all day.

We bought tickets ahead for two things: a bike tour of Versailles which included the train from Paris and entrance to the palace (although we paid less because we had a Paris Museum Pass). It was great fun to ride bikes through the village, stop at the market to buy lunch items, see all the gardens, canals and outside areas (Trianon, Marie Antoinette's farm) and then go into the Palace later in the day when it was less crowded. We were on our own for the interior (no tour guide), but that was fine with us. We also reserved an evening boat tour of the Seine which included access to the Eiffel Tower. We had a charming guide who had wonderful history of the Tower and Mr. Eiffel. We were on the Tower when the lights came on and it was lovely. Finally, we bought our Museum Passes at the airport -- very convenient.