This bell tower is all that remains of an old hospital, L’Hôpital de la Charité, which was built in 1633 and enlarged in the eighteenth century in order to serve the poorest people of the region.
The tower was built in 1804 for use as a baby hatch, where destitute mothers could anonymously leave their newborn babies. The mother was supposed to put the baby in a wooden cylinder and then ring the bell to alert the nurses that a baby was there. This baby hatch was in use from 1804 to 1843. The hospital itself was torn down in 1934 to make room for a public square, the Place Antonin Poncet, but the tower was left standing.
This is what the tower looks like from the Basilica Notre-Dame de Fourvière, on top of a nearby hill.
My photos in this post are from 2011. I revised the text in 2020.
See also: The baby hatch at the Maagdenhuis in Antwerp, Belgium.