Question

How long did the Conciergerie stay a prison and what did they do to the prisoners?

This is technically French History but I can't put two subjects down so I ask this instead.

Answer 1

From 1570 to 1649. (late sixteenth to mid seventeenth centuries)
The Conciergerie Palace was yet in the seventeenth century a very large jail in the Parisian landscape.
It welcomed the common prisoners from all the spring.

The Conciergerie was then the jail Revolutionary Court and be there meant almost certain to be guillotined.