Function IfDoublon(Produit As Range, Référence As Range) As Boolean
Dim Cel As Range
IfDoublon = False
If Produit.Value <> "" And Référence.Value <> "" Then
For Each sh In Worksheets
If sh.Name <> Produit.Parent.Name Then
Set Cel = sh.Columns("C").Find(Référence.Value)
If Not Cel Is Nothing Then
Set Cel = sh.Rows(Cel.Row).Find(Produit.Value)
If Not Cel Is Nothing Then
IfDoublon = True
Exit For
End If
End If
End If
Next
End If
End Function