Salut,
une proposition en vba, si j'ai bien compris la demande.
Ne pas oublier de cocher "Microsoft Scripting Runtime" dans l'onglet "Tools", option "References" de l'éditeur VBA
Sub try()
Application.ScreenUpdating = False
Dim dico As Variant
Set dico = CreateObject("scripting.dictionary")
Dim aa As Variant
aa = Sheets("journal des ventes").Range("A1").CurrentRegion
Dim i As Long
For i = LBound(aa) To UBound(aa)
If aa(i, 7) = "START PROG" Then
dico(aa(i, 2)) = ""
End If
Next i
Dim dl As Integer
With Sheets("inscription")
dl = .Range("A" & Rows.Count).End(xlUp).Row
For i = 2 To dl
If dico.Exists(.Cells(i, 1).Value) Then
.Cells(i, 15) = "START PROG"
End If
Next i
End With
Application.ScreenUpdating = True
End Sub