Option Explicit
Sub Concat_Tests()
Dim i As Integer
Dim d As Object
Dim c As Variant
Dim a
With Sheets("Feuil1")
Set d = CreateObject("scripting.dictionary")
For i = 2 To .[a65000].End(xlUp).Row
If Not d.Exists(.Cells(i, 1).Value & ":" & .Cells(i, 2).Value) Then
d(.Cells(i, 1).Value & ":" & .Cells(i, 2).Value) = .Cells(i, 3).Value
Else: d(.Cells(i, 1).Value & ":" & .Cells(i, 2).Value) = d(.Cells(i, 1).Value & ":" & .Cells(i, 2).Value) & " - " & .Cells(i, 3).Value
End If
Next i
i = 8
For Each c In d.Keys
a = Split(c, ":")
.Cells(i, 5).Resize(, 2).Value = a
.Cells(i, 7).Value = d(c)
i = i + 1
Next c
End With
End Sub