Neither Twinspires nor XpressBet has put up the Prix de l'Arc de Triomphe simulcasts on their schedule for the weekend? Details on Saturday and Sunday events are on the Thoroughbred Times link below:
http://www.thoroughbredtimes.com/racing-news/2011/09/22/amwest-to-distribute-arc-weekend-signal.aspx
Best weekend of racing in Europe - trust that the account wagering sites will get their act together and present the cards from Paris on Saturday and Sunday.