In 1984, France hosted very different Euros

Uefa was smaller in the Cold War era, and the 32 national teams who contested qualification included East Germany, Yugoslavia and the Soviet Union. The squads of the finalists comprised 20 players, of whom two could be used as subs in any match.
Disciplinary rules were different, too. Yellow cards from the qualifying competition carried into the finals. This gave France, who qualified automatically, an unfair advantage.