You can come via suburban rail (RER) B, station “Bagneux” (be careful, only half the trains stop at this station).
More information is available here
The talks and coffee breaks will be in room “Condorcet”, which is located in the building “d’Alembert” that can be seen on the picture below. Enter the building through the main entrance, turn left and take the staircase to the second floor.
After leaving the staircase through a glass door you should turn right to find the room at the end of the corridor (there is a rainbow above its entrance).
There will be signs to guide you to the room.
The only accomodation close to ENS Paris-Saclay is:
Séjours & Affaires Paris Bagneux (10 min. walk to ENS, ~100€ / night)
but the rer B line connects directly the ENS to Paris (10 minutes walk + 20 minutes train between ENS and the center of Paris) so any accomodation that is close to a rer B station will be convenient (see this page for an overview of the line together with the list of stations, this page for calculating travel times). Please contact the organizers if you need help.