Sub NomsFeuilles()
Dim i As Byte
Application.ScreenUpdating = False
Application.Calculation = xlManual 'évite le recalcul des formules
On Error Resume Next 'sécurité...
For i = 1 To Worksheets.Count 'renomme provisoirement les feuilles
If IsDate("1 " & Worksheets(i).Name) Then _
Worksheets(i).Name = CStr(i)
Next
For i = 1 To Worksheets.Count
With Worksheets(i)
If IsNumeric(.Name) Then .Name = _
Application.Proper(Format(.[D3], "mmmm")) & Format(.[D3], " yy")
End With
Next
Application.Calculation = xlAutomatic
End Sub