Sub test()
Set f1 = Sheets("donnee")
Set f2 = Sheets("feuil2")
Set d = CreateObject("Scripting.Dictionary")
For Each c In f1.[A2].Resize(Application.CountA(f1.[a:a]))
d(c.Value) = d(c.Value) & c.Offset(, 9) & " "
Next c
b = d.keys
For i = LBound(b) To UBound(b)
Cells(i + 2, "o") = b(i)
a = Split(d.Item(b(i)), " ")
f2.Cells(i + 2, "a").Offset(, 1).Resize(, UBound(a) + 1) = Application.Transpose(Application.Transpose(a))
Next i
End Sub