The time has come to sing the praises of that most wonderful of inventions, the Paris Pass. I know that many cities have similar passes, but it is the only one we've actually purchased. We looked into the Lisbon Pass, but quite frankly it is unnecessary. There are no queueing issues in any location in Lisbon - even the most popular sites.
But the Paris Pass is a different matter. We purchased the 4 day pass, which included 4 day public transport passes as well. We purchased 2 adult and 2 children's passes, though naturally the children's passes were much cheaper as they have free entry to all the museums. We got theirs for the transport pass.
Paris Pass is not cheap - initially. However, it provides you entry to dozens of places in and around Paris, and includes all of the most popular museums and places of interest EXCEPT the Eiffel Tower. Once you have visited a few of the sights you have made your money's worth back. If you are only going to visit one or two sights, you might not consider the Pass worthwhile, though there are 2-day passes as well. We used our Paris Pass to get into: the Louvre, the Musee d'Orsay, Versailles, the Musee du Moyen Age, the Sainte Chapelle, Musee de l'Orangerie, and took the free Seine River cruise that came included with the pass.
In terms of value for money, we definitely got our money's worth.
In terms of saving time, the Pass proved to be priceless.
Everywhere you visit in Paris has a queue. Some of them are long. Most of them are not popular with adults, and even less so with children. The longest we queued was about half an hour to go through the Palais de Justice security prior to entering the Sainte Chapelle. We could have queued for much longer. We simply walked in to the Musee d'Orsay, while the regular ticket line snaked out into the plaza in front of the museum. We got preferential entry into the Musee de l'Orangerie (where the queues were much shorter, but in the rain) - and they seem to limit the number of people in the gallery at any one time. And we didn't join any lines at the Louvre - again we simply walked in.
But the real benefit was seen at Versailles. The day we visited was very hot and sunny. Thousands of people visit Versailles. There is no limit to the number of people who can enter the Palace at any one time (unlike the Schonbrunn in Vienna, or the Alhambra in Granada). Our Paris Pass enabled us to join a very short queue - we were inside in about 10 minutes. The real ticket queue was tragically long. It wended its way up and down the forecourt and was at least 4 hours long. None of it was sheltered from the baking sun. I shudder to think what a waste of time that would have been, and what a ridiculous thing to do - either with or without children.
If only for that one experience, I would have still purchased the Paris Pass. We - all of us - had a fantastic time at Versailles. The Bookworm went nuts with her camera, photographing all the shiny, glittery things she could see (and there's a lot of that sort of thing!). Just to think... we could have spent all that time in a monotonous line with bored, whingey kids.
A word of caution about the transport tickets that come with the pass... Yvette was the custodian of the transport tickets in a pocket of her well designed travel pants. Unbeknownst to us - until it really mattered - the tiny magnetic pocket closures had demagnetised the tickets so they no longer worked at the Metro stations. We were stuck - several times - on railway platforms. And to prove that the Parisians are not as arrogant as their stereotype suggests, we got unsolicited instructions on how to get through the barricade without a functioning ticket from a very helpful woman. Owners of Scottevest with its myriad pockets, some with magnetic closures - beware - this applies to you too!
In short, the Paris Pass was one of the best investments we made for our holiday. We pre-purchased them via the internet from the comfort of our own home and they arrived not long afterwards in the mail. We simply took them with us, and they saved us both time and money wherever we went.