Private Sub Worksheet_Change(ByVal Target As Range)
Dim plage As Range
Set plage = [A:A] 'plage à traiter, à adapter
Set Target = Intersect(Target, plage, Me.UsedRange)
If Target Is Nothing Then Exit Sub
Application.EnableEvents = False 'désactive les évènements
For Each Target In Target.Areas 'si entrées multiples (copier-coller)
Target.Replace ",", ".", xlPart 'remplace la virgule par le point
Target = Target.Value
Next Target
Application.EnableEvents = True 'réactive les évènements
End Sub