This place rules!
My grandparents live in Nantes, where this is located, and I always stop by here on my way to visit them. My three year old daugther loves it almost as much as I do. The coolest thing, aside from the elephant, is the beautiful merry-go-round, with mantas, fish, and other sweet creatures.
It is absolutely worth the trip if you are in the Loire area.
You gotta love french state-subsidized art!