Sub couleur_bis()
Dim c As Range
For Each c In ActiveSheet.UsedRange
If c DIFF '' Then
lig = c.Row
col = c.Column
If InStr(1, Cells(lig + 1, col).Value, 'A') DIFF 0 Or InStr(1, Cells(lig + 1, col).Value, 'B') DIFF 0 Then
c.Interior.Color = vbBlue
End If
End If
Next c
End Sub