Option Explicit
Private Sub Worksheet_Activate()
Dim Dic As New Dictionary, T(), L&
T = Feuil5.[A2:B2].Resize(Feuil5.[A1000000].End(xlUp).Row - 1).Value
For L = 1 To UBound(T, 1)
Dic(T(L, 1)) = T(L, 2)
Next L
T = Me.[B2].Resize(Me.[B1000000].End(xlUp).Row - 1).Value
For L = 1 To UBound(T, 1)
If Dic.Exists(T(L, 1)) Then
T(L, 1) = Dic(T(L, 1))
Else
T(L, 1) = "(inexistant)"
End If
Next L
Me.[E2].Resize(UBound(T, 1)).Value = T
End Sub