bonjour,
une solution via une macro
Sub test()
dl = Cells(Rows.Count, 1).End(xlUp).Row
For i = 1 To dl
For j = 4 To 5
If Cells(i, j) = "" Then
For r = i - 1 To 1 Step -1
If Cells(i, 3) = Cells(r, 3) Then
Cells(i, j) = Cells(r, j)
Exit For
End If
Next r
End If
Next j
Next i
End Sub