Where to sleep?

The city of Reims has several hotels near the festival and there are some campsites in the surrounding cities:

https://www.google.fr/maps/search/hotels+reims/@49.2525728,4.0227234,15z?entry=ttu

are in a motorhome, you have a parking lot near the International Residence Center (CIS) with 9 spots (5 minutes walk to the Festival):

https://www.grandreims.fr/se-deplacer/les-aires-de-camping-cars-et-campings