I hope you're not too intent on seeing the Pantheon, its in Rome. But I'm taking a vacation to London and Paris in November and those other things are some good places I've looked into. I would also add to that list the Jardin du Luxembourg. Its a large public area with a palace in the middle from the 1600's.
While you are at the Jardin du Luxembourg you might want to pay a visit to the Paris Pantheon and the Sorbonne a few blocks to the east of the gardens (metro Cardinal Lemoine). Hungry? Try the rue Mouffetard farmer's market before 1PM.
2)Louvre (not going inside)
4)Arc de Triumphe
9)Hotel de invalides (unfortunately it was closed by the time we got there)
10)Palais de chaillot
12) Moulin Rouge and the Montmarte cemetary
(plus a lot of detours because I'm terrible and reading maps but refuse to let other people help me)
in 12 hours.
We didn't really get to see everything to the smallest detail... but considering we only had 12hours I think we saw quite a bit.
You should be able to see all of those 3 days if I manage in 12 hours (and I'm slow and big and dillying around!!)
im going to be in lyon in a few weeks whats there to do there?
U absolutely have to see the Eiffel tower. The most famous attraction.
But there are long queues for a lot of the attractions, so go to them, in order of preference, in case there is not time, for all. Sometimes the queues are hours long.