Sub Formule()
Dim F$
Dim DernLigne As Long
DernLigne = Range("A" & Rows.Count).End(xlUp).Row
F = "=IF(AND(RC[-3]=RC[-1],RC[-2]>=RC[-4]),""J"",IF(RC[-2]<=RC[-4],""L"",IF(ROUND(RC[-2]*VLOOKUP(RC3*1,'[Taux conversion]Feuil1'!R1C1:R56C7,6,0),3)>=RC[-4],""J"",""L"")))"
Range("J2").Formula = F
Range("J2").AutoFill Destination:=Range("J2:J" & DernLigne), Type:=xlFillDefault
End Sub