There are a lot of very nice hotels in Paris. We would recommend to book a hotel in the Saint Germain area or at least very close to it as all events will be happening in or close to that area. Having said this, we were able to negotiate a special price at the iconic hotel Lutetia and we will also stay there. Here are more details:

Hotel Lutetia
Address: 45 Bd Raspail, 75006 Paris (Google Maps)
Price per standard room: 450€ (special discount from 950€).
Please contact Servane Marivain: ‎servane.marivain@hotellutetia.com, ‎+33 1 49 54 46 45
Website: www.hotellutetia.com