Only two hotels (Residhome and Hotel d'Orsay) are at walking distance from the conference place. But you can also stay in Paris or in Gif-sur-Yvette.
It takes about 35 mn RER + 15 mn walk within the campus to come to the Laboratory of Theoretical Physics from Paris - e.g. from Luxembourg RER station, and 5 mn RER + 15 mn walk from Gif-sur-Yvette
From Paris or from Gif-sur-Yvette, there is a RER at least every 15 mn.

Hotel lists

In the hotel lists below, phone numbers are given for a call from France (01 ....). For calls from abroad, you should replace 01 by 33-1.