Dim wb As Workbook
For Each wb In Workbooks
If wb.Name = 'bonjour.xls' Then
MsgBox 'Le classeur bonjour.xls est ouvert'
Exit Sub
End If
Next wb
Function Ouvert(ByVal NomFichier$) As Boolean
Dim Wbk As Workbook
On Error GoTo fin
Set Wbk = Workbooks(NomFichier)
Ouvert = True
fin:
End Function
If Ouvert('Bijour') Then
Msgbox 'Bijour Mr Vincent'
End If