For Lig = 1 To DLig
For Lig = 1 To DLig + 1
......
An_ok = False
VAn = Sheets("Feuil1").TextBox1
For n = 1 To Sheets("Donnée").Range("A65536").End(xlUp).Row
If Year(Sheets("Donnée").Range("A" & n)) = VAn Then
An_ok = True
Exit For
End If
Next n
If An_ok = False Then
MsgBox ("Cette Année n'existe pas")
Exit Sub
End If
FirstCel = "": LastCel = ""
.........