Just ask the friend who visited last week. When I heard she had a friend from Germany who would come see Paris with her, I jumped for joy and let her go on her own! But I agreed to go to Paris with the family members visiting this week.
We had an adventure getting on the train - I wasn't sure I'd find a spot at the train station to leave the car all day, so we had Frédéric take us in two groups. I went with the first group, and we bought everyone's tickets, and waited for the second group. And waited. And waited. I cut the timing a little too close - they pulled into the station just as the train did, and we still had to run underground to the other platform. But we made it!
We started out by taking a peek at Notre Dame, and then the Luxembourg Gardens. After that, we hopped on an RER to go look at (but not go up in) the Eiffel Tower.
My friend who came last week went to the Arc de Triomphe so she could get a view of Paris including the Eiffel Tower. We thought that sounded like a good idea, so we did that, too.
There are not as many stairs as the Eiffel Tower, but they were spiral, so you get dizzy, too.
It was hot, hot, hot, hot! After the Arc de Triomphe and a stroll down the Champs-Elysées, we decided we had seen enough of Paris. We caught our train back home, and made a bee-line for the kids' pool once we got there.