WWE's Chris Jericho Almost Arrested

It all went down during a match between Jericho and C.M. Punk -- who was proudly waving the flag in the ring. Jericho took the flag away, crumpled it up and kicked the flag out of the ring ... and that's when police stepped in and put a stop to the event.

We're told Jericho was informed that desecrating the national flag is a crime in Brazil ... punishable by incarceration.

Cops gave Jericho an option -- apologize to the arena ... or go to jail. Chris chose the former ... grabbing the mic and telling the crowd he immediately regretted his actions. Cops allowed the event to continue.

Sources connected to the WWE tell TMZ ... the flag stunt was NOT planned or approved by WWE officials.