You can access here the official calendar of the trimester Random Walks and Asymptotic Geometry of Groups.
Below are some non-necessarily math-related events that may be of interest for participants of that program:
For those who feel like breathing a bit without going outside Paris, along the Seine you can have a not too polluted walks. Check here for more details. You can also breathe a bit in the Jardins du Luxembourg very close to IHP, or the Jardin des Plantes near Jussieu.