Yes.
It seems that hooligans posted pictures and statuses of what will happen on social media a few hours before a match.
Croatian police reported that to Uefa and French police.
French police still let those guys in, even though they had a suspicion that they will cause problems.
French police knew about 3 different plans, one was entering a pitch, and in some media it says that a plan was to attack a referee or some players also, to cause even bigger mess.
Also, it was clear that French police knew what was going to happen since hooligans planned to make problems in the 85th minute of the match.
Around minute 75-80, a lot of French policemen came to that part of a stadium where these hooligans were standing.
So, police knew what will happen.
Police let them in.
Hooligans somehow brought flares into the stadium.
Police knew about the plans and in the 80th minute, they wanted to stop possible invasion on the field, but they couldn't stop flares.
I also don't know what Croatian FA could have done here.
Further, again on social media we can read these days that they are planning new attacks on Spain:Croatia match.
There are even pictures and a few possible scenarios what will happen on the match, available...
If Croatia gets some punishment, that is insane:
1. Croatian FA reported these hooligans
2. French police knew/knows about them
3. French police is letting them in
4. Croatian FA is surely reporting new attacks for Tuesday
Ok, things which Croatia can do or could have done is to give 10 years prison jails to guys who are doing this and similar things.
Plus, to not allow hooligans to leave the country during the Euros...
For guys outside of Croatia, we can read here that fans of St Etienne helped to Croatian hooligans, they bought tickets for them and some sources claim that St Etienne fans actually entered flares into a stadium and passed them to Croatian hooligans.
So, French idiots from St Etienne who love to fight against "the system" helped to Croatian idiots who's only purpose in life is to fight against the system.