Sub Inserer_une_ligne()
Dim Dli As Long, EtatInitCalcul
EtatInitCalcul = Application.Calculation
Application.Calculation = xlCalculationManual
Dli = Cells(Rows.Count, 1).End(xlUp).Row - 3
Rows(Dli + 1).Insert Shift:=xlDown
Range("A" & Dli & ":N" & Dli).Copy Range("A" & Dli + 1)
Range("A" & Dli + 1 & ":M" & Dli + 1).ClearContents
Application.Calculation = EtatInitCalcul
If EtatInitCalcul = xlCalculationManual Then ActiveSheet.Calculate
End Sub