The RER B does not stop at Gare de Lyon. There is a Novotel near Le Halles by the Chatelet stop. Or I prefer the Hotel Jardin du Luxembourg near the Luxembourg stop on the RER B which is always €135. It is a very nice boutique hotel and they have WiFi on floors 4, 5 & 6. T2 at the airport is abou 40 minutes door to door from this hotel. 45-60 minutes to T1.