Dim i As Long
Dim taille As Long
taille = ThisWorkbook.Worksheets("Prix").Cells(Rows.Count, 1).End(xlUp).Row
For i = 1 To taille
ThisWorkbook.Worksheets("Prix").Cells(2, 2).Offset(i) = Application.VLookup(ThisWorkbook.Worksheets("Prix").Cells(2, 1).Offset(i).Value, Workbooks("C:\Users\pc\Desktop\B").Worksheets("Donnees").Range("B:D"), 3, False)
Next i
End Sub