I have searched a bit on the internet about the Hotels in Paris, they are really too expensive around the Champs Elysées, about 500€ per night, but the best way would be to get an hotel on the fastest way.
I have choosen the Hotel Ibis because it's not overpriced (Ibis owns a lot of Hotels).
Prices depends on when you come, here they are for one room :

If I understand well their thing, it's for one person... but if you want more details, I can call them
Moreover, tomorrow I'll try to call them and be sure those concerts are confirmed, please don't do anything until we are sure it'll take place !!
Anyway, I will let you know as soon as possible about all mess !
Regards,
Nicolas