bonjour,
solution via une macro
Sub aargh()
Set ws1 = Sheets("id_mess")
Set ws2 = Sheets("données")
dlws1 = ws1.Cells(Rows.Count, 1).End(xlUp).Row
dlws2 = ws2.Cells(Rows.Count, 5).End(xlUp).Row
With ws1.Range("B2:B" & dlws1)
For i = 2 To dlws2
Set re = .Find(ws2.Cells(i, 5), lookat:=xlWhole)
If Not re Is Nothing Then
ws2.Cells(i, 4) = re.Offset(0, -1)
End If
Next i
End With
End Sub