We stayed on the Left Bank at the Hotel Left Bank in St. Germain, which I highly recommend. Book the suite on the top floor. It is a bit more expensive than their other rooms, but it's so worth it. It is the perfect size for a family and you get a fabulous view of Notre Dame. Ooh, la la.
The Left Bank is not as touristy as other areas in Paris and the restaurants and hotels are generally less expensive. But, you can walk to almost all of the sights. If not, the subway system is great. We took the subway to the Eiffel Tower after dark with the girls and felt very safe.
Now, if you are in Paris and don't visit the Louvre, you are crazy. We booked a tour of the Louvre through Paris Muse and it was fantastic. If you are visiting the Louvre for the first time, especially with kids, you should really book a personal tour. It's an "investment," but well worth it! Your guide will whisk you through the highlights and engage your children throughout the tour with a "scavenger hunt."
We absolutely loved our tour guide, Davinia and my opinion of Parisians was slowly turning around, except she was a Brit! Oh well.
If you want a more manageable museum, you should also visit the Orsay museum on the Left Bank. It is housed in a former train station... a bit odd, but a real gem.
Of course, you cannot leave Paris without a visit to the Eiffel tower. We decided to go at night to see it lit up. The girls loved it at the top of the hour when the lights starts to blink and everyone cheers. It's a celebration every hour!
The lines are much shorter late night, so make this visit on your 1st or 2nd night when your body clock is still confused. We traveled from NYC, so visiting the Eiffel tower on our 2nd night there at 11pm was no problem for the girls.
You must also visit Sacre Couer. You will get a great view of Paris from the highest point in the city.
One of my favorite sights was the "love bridge" that we crossed from the Left Bank every day... People have written their names on these locks and thrown the key into the Seine. There are hundreds of them and it just puts a smile on your face...
OK, I do love Paris!