French autorities say that banning away fans for this match had little to do with the safety for Ajax fans but rather the safety for the Marseille fans. "Agressive behavior is something that is seen a lot with Ajax ultras, who mostly operate under the name 'F-Side'. They are known as one of the most dangerous groups of Europe."
In 2009 things already went wrong between the two clubs when Marseille and Ajax faced eachother in the UEFA cup. Ajax fans went with a big group of fans to Marseille. Ajax fans were then attacked by Marseille fans with bricks, sticks and iron bars. Ajax fans then chased Marseille fans until police showed up. In the return in Amsterdam Ajax fans held up a banner saying "We had joy we had fun, we had L'om on the run".
We are not angels, but a little bit self reflection is needed after they allowed Marseille fans to bombard the Lyon coach (injuring him), and teambus with stones.
It’s ok though, after investigating themselves, everyone concluded they did their job correctly.
The game will be (re-)played in Marseille as if nothing happened. No sanctions no blames. All good.
You expected something else from French bureaucracy? Anything they can do to not actually have to do anything