回複：買個Paris Museum Pass

不用提前買。

The Paris Museum Pass provides unlimited access during its period of validity to more than 60 museums and monuments in and around Paris. Besides its convenience, it can save considerable amounts of time by permitting you to by-pass long ticket lines.

http://www.tripadvisor.com/Travel-g187147-c3012/Paris:France:Paris.Metro.Museum.Passes..html

http://en.parismuseumpass.com/