Participants will be staying in the newly renovated pilgrims' quarters, located in the former Grand Seminaire. Below are detailed instructions on how to get to Chartres, and to the Grand Seminaire, as well as a number of the hotels. Trains to Chartres leave from the Gare Montparnasse, one of six train stations in Paris.
Shuttles are an alternative, and are described below.
I'll be seeing you in Chartres. It is not necessary to be an Air France customer to use their bus service. At Charles de Gaulle Airport, most airlines from the United States arrive at Terminal 2, Area 2C. The Air France bus stop is between Hall C and Hall A. Follow the signs towards Hall A and you will see the exit which is marked for the Air France bus. They are large white buses. I suspect that the bus also stops between Halls B and D, although I have never seen an American flight come in there.