Disclosed is a configurational stereoisomer, named enantiomer E3, of flocoumafen, the enantiomer E3 having, by chromatographic analysis of flocoumafen performed under particular conditions, a retention time t3 having a value such that t1<；t2<；t3<；t4； t1, t2 and t4 representing the retention times of the configurational stereoisomers of flocoumafen different from the enantiomer E3, the analysis being performed at a temperature of 23.5° C.
