The Sézanne flora is a fossil assemblage preserved in freshwater limestone deposits at Sézanne, laid down during the Thanetian age, when Europe enjoyed a tropical climate.
The first specimens were found from the Danata Formation Lagerstätten, of the Thanetian epoch of Turkmenistan, where they were originally thought to be smaller or juvenile individuals of the true louvar, Luvarus necopinatus.
It contains only one species, Prohepialus incertus, which was described from a Thanetian crater lake diatomite (Paleocene) in Menat (Puy-de-Dôme), France.