Sub Marquage1()
Dim j As Byte, k As Integer, Mavariable As String, trouve As Boolean
trouve = False
For j = 1 To 3 'On scanne les 3 cellules
For k = 1 To Len(Cells(1, j)) 'On scanne chaque caractère de la cellule
If Cells(1, j).Characters(k, 1).Font.ColorIndex = 3 Then
Mavariable = Cells(1, j).Address: trouve = True: Exit For
End If
Next k
If trouve = True Then Exit For
Next j
MsgBox Mavariable
End Sub