I am booked on the 7 day RS Paris tour and am trying to plan out my free time. Because some things are better booked way in advance, I am trying to decide if I should book a visit to Sainte-Chapelle, now for May. I did read somewhere that on one tour, the tour guide offered to do so for people interested in going. Has anyone else had this option? I wouldn't mind waiting because the date the tour guide offers would probably be the best day to go however, I don't want to chance the tickets being sold out.