Const T As String = "C:\Users\xxx\AppData\Roaming\Microsoft\Templates\Charts\Graphique1.crtx"
Private Sub Worksheet_PivotTableUpdate(ByVal Target As PivotTable)
Dim objchart As ChartObject
Set objchart = Me.ChartObjects(1)
objchart.Chart.ApplyChartTemplate (T)
End Sub