Envision a playful, modern, hands-on science museum for children in bright state-of-the-art surroundings.
Then, picture the exact opposite and you have a fair idea of where I took my 9-year-old yesterday.
The planetarium was OK, that is the best I can say about this place.
If you have a Sunday to spare and nothing to do, then sure, why not go? It's better than watching TV.
If, however, your time in Paris is limited, then take your bambini to La Villette, instead.