France hosted the rugby final earlier on the day and also women's game ran smoothly as well without any issues, not to mention the Monaco F1 race. The issue is that a lot of travelling football fans tend to come from lower social classes with minimal education and all this coupled with foreign police, this is a huge recipe for disaster.
The Euro 2021 was a travesty last year in London yet the Olympics hosted 9 years previously went so smoothly. Football fans are always the huge issue, no matter how much we blame the authorities.