Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Range("monchamp"), Target) Is Nothing And Target.Count = 1 Then
For Each c In Range("monchamp")
If UCase(c.Value) = UCase(Target.Value) And c.Row <> Target.Row And c.Value <> Empty Then
MsgBox "Doublon en :" & c.Address & Chr$(10) _
& "Date remise:" & c.Offset(0, 1) & Chr$(10) _
& "Montant:" & c.Offset(0, 1)
Application.EnableEvents = False
Application.Undo
Application.EnableEvents = True
Target.Select
End If
Next c
End If
End Sub