...
If CStr(Range("G" & n)) = ComboBox5 And CStr(Range("D" & n)) = ComboBox20 Then
'---------------- ici --------
If Right(Range("C" & n), 1) = "#" Then
ComboBox10 = Left(Range("C" & n), Len(Range("C" & n)) - 1)
Else
ComboBox10 = Range("C" & n)
End If
If ComboBox10.ListIndex = -1 Then ComboBox10.AddItem Range("C" & n)
End If
...