Ms Galore, I too would recommend Roissybus as suggested by someone already. Leaves from Opera just round the corner from Galeries Lafayette. BAAZ I think the fare has gone up to €9.10 though!

I would also suggest visiting La Vallee Village. Such a pity Alexandre de Paris is no longer there but there are a few worthwhile stores (however, Bicester Village is better for some things!). It is easy to reach from CDG. Hop on a TGV to Parc Disneyland (about 15 min) and then catch a taxi from there or it is one stop from Parc Disneyland on RER. Do not go there when it is raining, for it is an outdoor outlet shopping centre (but there is an indoor shopping centre next to it).