Sub Test2()
Application.ScreenUpdating = False
On Error Resume Next 'si aucune SpecialCell
With ThisWorkbook.Sheets("Base").[G50:AMC15000]
.Replace ComboBox1, "#N/A", xlWhole, MatchCase:=True
.SpecialCells(xlCellTypeConstants, 16).Offset(, 1) = ComboBox2
.Replace "#N/A", ComboBox1
End With
End Sub