We went to the Versailles exhibition at the Science Museum which is very well worth seeing: beautiful and fascinating things, many of which are totally unexpected; very well displayed (it’s not clear by whom, maybe inhouse); and deeply informative.
It’s not really about Versailles or only tangentially, but about the relationship of science to the French state and the way it was promoted by the French crown through the Académie Française and financial support for the work of individual scientists: gardens, plants, medicine, zoology.
The Marly Machine, which pumped water by a massive aqueduct to Versailles:-

Fountainheads:-

Peter Boel, Study of a cassowary:-

Model of a new-born baby to teach obstetrics:-

‘Marie-Antoinette’ Breguet No.160 Watch:-

Model of a chemistry laboratory:-

Not so many people so you are not jostled going round it.