3 nights in Paris with a 7 and 5 year old

Have you reviewed any of the Rick Steves guidebooks for Paris and London? He has 22 pages in his Paris guidebook devoted to "Children in Paris." If don't want to buy the book then check it out from your local library travel section. That is a standard feature in most of his guidebook especially the city books.

Your friends in France have no suggestions?

Here is advice that always applies to these frequent general questions: First, go to the Explore Europe menu on the top left of this page, then click your way to Paris. You will find plenty to think about. Frankly, why should these tips be repeated over and over for first-timers on this website?. Plus you will gain context to the answers you may receive to more specific questions. You will be better able to understand the suggestions.

Stay by Canal St Martin. VRBO has some cute apartments there

I am a Right Bank person these days but I think you should stay in Saint Germain or the Latin Quarter.

When I first visited Paris, my Son was 7 and the things that he loved were the Eiffel Tower and Seine River cruise.