Option Explicit
 
Private Sub ConcatenationCSV(sDossier As String)
Dim Wkb As Workbook
Dim sChemin As String, sFichier As String
Dim LastRow As Long, iRow As Long
Dim c As Range, Ar() As String
Const sSeparateur As String = ";"
 
    Application.ScreenUpdating = False
     
    sChemin = sDossier & "\"
    sFichier = Dir$(sChemin & "*.csv" )
 
    Feuil1.Cells.Clear
    Do While Len(sFichier) > 0
     
        Set Wkb = Workbooks.Open(sChemin & sFichier)
        LastRow = Wkb.Sheets(1).Cells(Wkb.Sheets(1).Rows.Count, 1).End(xlUp).Row
 
        With Feuil1
            For Each c In Wkb.Sheets(1).Range("A1:A" & LastRow)
                iRow = .Cells(.Rows.Count, 1).End(xlUp).Row + 1
                Ar = Split(c, sSeparateur)
                .Range(.Cells(iRow, 1), .Cells(iRow, UBound(Ar) + 1)).Value = Ar
            Next c
        End With
         
        Wkb.Close
        Set Wkb = Nothing
         
        sFichier = Dir$()
    Loop
    Application.ScreenUpdating = True
End Sub
 
Sub SelDossierCSV()
    With Application.FileDialog(msoFileDialogFolderPicker)
        .InitialFileName = ThisWorkbook.Path & "\"
        .Title = "Dossier CSV à traiter"
        .AllowMultiSelect = False
        .ButtonName = "Sélection Dossier"
        .Show
        If .SelectedItems.Count > 0 Then
            DoEvents
            ConcatenationCSV .SelectedItems(1)
        End If
    End With
End Sub