I'd say France, Germany and Spain are the prime favourites for the tournament. I think Germany and Spain have the best squads in terms of individual quality, France may be a level below them in that regard, but home advantage puts them at a par with them in the coming Euro's.
Germany is pretty clearly the top favourite imo, afterwards there's France & Spain, followed by Belgium and the rest (you should never discount Italy, they kinda always have the potential to either win it or drop out at group stage).