Private Sub Worksheet_Change(ByVal Target As Range)
Range('D1') = ''
If Not Intersect(Target, Range('C3')) Is Nothing Then
If Range('C4') <> Range('C1') + Range('C2') + Range('C3') Then
MsgBox ('ERREUR SUR TOTAL DES 3 CELLULES')
With Worksheets('Feuil1').Range('D1')
.Font.ColorIndex = 3
.Font.Bold = True
.Font.Name = 'Arial'
.Font.Size = 14
.Font.ColorIndex = 3
End With
Range('D1').Value = 'ERREUR DE SAISIE'
End If
End If
End Sub