We found it! After taking so many of these boats for fifty years, I can say that the little VEDETTES de PARIS filled the bill.
We went on a family-oriented cruise with a French and English speaking trained guide who asked the children questions. The cruise is advertised as Croisiere familiale, or Family cruise and it's child friendly. They offer a couple of family cruises a day, but everyone is welcome. You don't have to have a child with you to enjoy!
You can find the company at the foot of the Eiffel Tower. It's the smaller one, with smaller boats that are all converting to electric motors. When the owner realized the impact all the boats were having on the health of the Seine, she decided to convert to electricity from diesel. My husband heard about this on French radio.
Another difference: you won't see all the tour buses parked here like you will for the Bateaux Mouches and other large boats.
But the most important difference is that this has a live, human guide, not a fuzzy tape recorded in four languages. Bon voyage.