You can take a taxi, it takes about 45 minutes (60 to 70 euros). You can take the Metro, about an hour (10 euros).
Take the RER B towards ROBINSON, stop at “Saint-Michel-Notre-Dame” Station
Then, take Line 4 towards MAIRIE DE MONTROUGE and stop at “Saint-Germain-des-Prés” Station.
Walk for 2 minutes. The hotel is located at Rue Saint-Benoît, 24.