1. The 'police' in French stadiums are not actually police.
2. In France the 'police' deal with minor neighbourhood issues. The officers present at football matches are CRS.
3. The CRS are a military force, created to avoid any links with local community. In essence, they don't care about keeping good relationships with anyone.
4. CRS training is all about use of tactics and force to contain or subdue incidents. They are incredibly disciplined and ruthless.
5. Faced with a large group of rowdy English fans who chant anti-ISIS slogans at locals, they will use tear gas, water canons and batons freely and liberally.
6. In France, citizens are required to carry ID at all times. A CRS officer will begin any conversation with a possible suspect with 'where is your ID?'.
7. If you don't immediately produce ID, you are liable to be arrested. You are in breach of the law.
8. If you do produce ID, the officer can confiscate it without proceeding to an arrest, effectively forcing you to follow him to a van or detention centre to avoid falling foul of the law.
9. The CRS carry multiple weapons and tear gas. They won't hesitate to use them.
10. The CRS are mostly nationalistic and proudly right wing. Many are of North African descent. If they see tattooed English skinheads causing trouble or provoking the local teenagers, they will take great pleasure in doing the above in
Order to maintain order.
In short: for your own good, don't screw with the CRS. While your sunburned English behinds are drinking in their stadium, they are bored, and quietly hoping for a chance to use their training on a football lout from the land of Carling and boiled beef, and teach him a lesson in French (or Algerian) civility.