Which is ironic because the Roissy bus starts at Opera, runs express to the airport and costs €10. If you were anywere else in Paris, I'd understand it
Being a Parisian, I am aware of that. It is s very handy shuttle and would usually take it before catching a train from St Lazare if heading to the family home. I was attending a friend's birthday in the area and had booked a hotel for one night only and did not feel like being on the bus! I enjoyed the door to door service!