We just returned from a week in Paris and have two new (still in the plastic wrap) 4-day Paris Museum passes for sale. It turns out, handicapped persons (my mom uses a wheelchair) with their helper get into museums free (as do children ages 18 and under with an adult paying for a ticket). We have two passes to sell. They originally cost 56 Euros or $62.59, each. They are good until 2016--once you sign and date the pass it then is only good for four consecutive days.
The pass is the way to go if you want to see the sites: museums, palaces, arches etc. Not only do you save money, you by-pass all lines. We entered every venue looking at long lines and waltzed right in the special group entrances. We saved multiple dollars and hours of time.
We are selling them for $120.00 for both passes.