Bon, je met le code, ce sera peut etre plus simple:
Private Sub Worksheet_Activate()
Dim r As Integer
Dim datetest As Date
datetest = Now()
r = Format(datetest, "ww", vbMonday, vbFirstFourDays) + 1
Columns(r + 7).Interior.Color = RGB(220, 220, 220)
For i = 1 To 4
Cells(i, r + 6).Interior.Color = Cells(i, r + 5).Interior.Color
Next i
End Sub