Does the Paris Pass "activate" the first day it is used or the day that it is purchased?

From the Paris Pass site: "The Paris Pass comes in 2, 3*, 4 and 6 day durations to suit all kinds of trips, from short weekend city breaks, to longer vacations. Your Paris Pass is activated the first time you scan it through at an attraction and is valid to use for consecutive days of your Pass duration – 2, 4, 3 or 6 days."

*The 3 Day Paris Pass comes with a 2 day Museum Pass.

Have you compared the Paris Pass to the Paris Museum Pass? We found that it was more economical to purchase a Paris Museum Pass and to then purchase a carnet of metro tickets.

For only 2 days, you are throwing money away with the Paris Pass. Just get the Museum Pass, which is included with the Paris Pass, which is just a bundle of other products, packaged, marked up and sold to the unwitting.

There is no such thing as a 'Paris Pass' if by 'Pass' you envision a single card that can be used for museums and transport and such. It is a marketing scheme to sell you the ordinary museum pass and the ordinary and overpriced Paris Visite and charge you more for it. So the Museum Pass that comes with your package starts the first day you use it and runs consecutive days, but you don't need to start it the same day you start using the Visite which is turned on the first day you use it and runs consecutive days. When you buy it is irrelevant. The HOHO pass that comes with the kit also becomes active when you use it etc. It is almost never a wise purchase but if you have one already, you can use the component parts as you choose not necessarily the same days.

"Activating" the Paris Museum Pass is up to you - you write the date onto it that you want it to start.