I could imagine/speculate about some things that might meet the definition, but I don’t know. What’s a false flag?
A . .
government/oligarchy
planned, sponsored, implemented trauma, disaster, attack made to look like XYZ enemy(ies) did it.
When I was in Asia the first time (Viet Nam war time), I came across a plan to blow up a French ship in Hanoi harbor and make it look like the NVietmese had done it etc.
CINCPAC at the time, McCain, nixed it.
The oligarchy seems to love that sort of thing.