Lyon has a well established tourist industry, and is well used to hosting large-scale events such as the annual Fete des Lumieres which attracts more than 4 million visitors (cancelled this year in the wake of the Paris terror attacks), so the accommodation picture in Lyon is better than in some other host cities.
Which is just as well, as Lyon will also likely be serving as a base for a significant number fans whose teams are playing in nearby Saint Étienne, which doesn’t have the same tourist infrastructure as its larger neighbour. So do bear in mind the fixtures down the road as well as those at the Parc Olympique Lyonnais when planning a visit or making reservations.
The city is split into districts, and most of the hotels fall into one of three - Presqu’ile (the main city centre, the ‘island’ between the two rivers), Croix-Rousse (the hill to the north of the city) and Confluence (south of the main city centre, where the Rhône and Saône meet). Some hotels are also found out in the 6eme district of Brotteaux to the east, near Part Dieu railway station, but these are more aimed at business travellers than tourists.
The tourist office offers an online booking portal for accommodation throughout the city - you can find it at www.en.lyon-france.com/ .
Uefa also has an official accommodation partner - HomeAway (www.homeaway.co.uk/euro2016/) which works on a similar basis to Airbnb, offering flats, apartments and houses in and around host cities. Their search function splits properties between each host city, making it easy to use.
If you can’t find accommodation in the city itself, then Grenoble and Valence are within relatively easy commuting distance to the south, and you could even explore Geneva just over the Swiss border, which is served by a regular train service, although any savings from not being a host city are likely to be offset by the higher cost of living in Switzerland.