Sub Mise_en_forme()
Application.ScreenUpdating = False
Dim s As Worksheet
For Each s In Worksheets
Set Plg = Range("F2:AS" & Cells(Rows.Count, 1).End(xlUp).Row)
For Each C In Plg
Select Case C.Value
Case "M"
C.Interior.ColorIndex = 35
Case "P"
C.Interior.ColorIndex = 37
Case "C"
C.Interior.ColorIndex = 44
Case "F"
C.Interior.ColorIndex = 46
Case Else
C.Interior.ColorIndex = xlNone
End Select
Next C
Next s
Application.ScreenUpdating = True
End Sub