The 2021 Cannes film Festival will exceptionally take place in JULY (6th to 13th).
If you do not come to Cannes for this reason, it's better to avoid this period to visit the town. The hotel rooms are outrageously expensive, the restaurants overcrowded and the crowd is everywhere.
If you want to attend the Festival, to accomodate yourself at lower prices, but with more commuting do not forget the neighbouring cities linked by the Cannes buses : La Bocca, Mandelieu, Le Cannet, (forget your car during the Festival. using it and parking it is a nightmare).
You can also choose a further hotel and come by train : the Cannes train station is only 5mn walk away from the Festival palace. Golfe Juan, Juan les Pins, Antibes, and even Nice are on the coastal line with many trains. See Around Nice by train. Fréjus is also an option but with less trains. An other possibility to commute from/to these cities : the Departement buses (line 200 to Nice, 600 to Grasse, with even night buses on some days) But beware : the trip to Nice lasts 2hours instead of 30-40mn by train.. The bus station is also 5mn away from the palace, next to the city hall.
For those who love movies, the Festival is an opportunity to discover films before everyone else, to glimpse movie stars and somtimes to get autographs.
The program is available on the official site of the festival.