I suspect the word "FLOOR" comes from a literal translation of the French.
It is probably to do with a line on a graph, maybe at the bottom.
On the Mk 1 Airbus (A300) it is triggered by AoA. 6 degrees with slats retracted and 9.5 to 11.5 degrees with slats extended.
We sometimes get it when in a turn just above V4 when the slats are selected to retract. The N1 caption flashes on the FPI on some aircraft depending on the mod state. The power is already at the N1 limit so otherwise we would not know.