The most delightful way of getting to Trentemoult is the Navibus (river shuttle).
It's a small public boat which links the centre of Nantes to the banks of Trentemoult, on the other side of the river Loire.

It's exactly what we did and we found ourselves projected into a kind of slow time machine, which didn’t transport us only to the other shore of the river, but also 40 or 50 years backwards, directly into the scenery of an old black and white French movie, with all the typical characters, a little naive in their fixed typology, but so pleasant and attaching at the same time.