Sub essai()
Dim i As Integer
Dim j As Integer
For i = 3 To 1000
If Cells(i, 3) = "" Then Exit Sub
For j = 3 To 1000
If Cells(i, 3) = Cells(j, 5) Then
Range(Cells(i, 3), Cells(i, 5)).Interior.ColorIndex = 6
Range(Cells(j, 3), Cells(j, 5)).Interior.ColorIndex = 6
MsgBox "Doublon N°" & " " & Cells(i, 3) & " " & "ligne N°" & " " & i & " " & "et ligne N°" & " " & j
Exit For
ElseIf Cells(j, 5) = "" Then
Exit For
End If
Next j
Next i
End Sub