The Air France coaches that shuttled passengers between Paris and Roissy-CDG or Orly airports is now called Le Bus Direct (which is probably good because the old name made people think only Air France passengers could use it).
There are four lines with multiple stops: two to Roissy-CDG (€17 one-way), one to Orly (€12 one-way), and one between Roissy-CDG and Orly (€21 one-way). As usual there are stops at Gare de Lyon, Montparnasse, Porte Maillot and Arc de Triomphe, but now there are also stops at Trocadéro, the Eiffel Tower, and La Motte Piquet. The buses have free Wifi and USB plugs at each seat. Open daily 5am-11:40pm, buy your tickets online in advance to save time.
Don’t confuse this bus service with the RATP-run RoissyBus (from Opéra for €11 one-way) or OrlyBus (from Denfert Rochereau, €7.70 one-way), which is basically a Paris city bus, so not as comfy but less expensive and possibly closer to where you want to be dropped off in Paris, and you can use your Navigo pass or 5-zone Paris pass.