Dim extract As Workbook, Nom_Fichier As Variant, nblig As Long
Dim WbS As Workbook
Set WbS = ActiveWorkbook
ChDrive ("F:") 'tu pointe le bon disque
ChDir "F:\mondossier" 'tu pointe le bon dossier
Nom_Fichier = Application.GetOpenFilename("Fichiers Excel (*.xlsx), *.xlsm")
If Nom_Fichier = False Then Exit Sub
Set extract = Workbooks.Open(Nom_Fichier)
extract.Activate