Then I would fly Eaysyjet at 11:55 on Saturday. You avoid the dreaded AF A318 and get a much cheaper deal. With first row and one bag, ticket currently costs 162 instead of 282 on AF1179 at 12:45.
Traffic is going to be light on Sunday morning so taxi to airport will be fine.
Flying Sunday morning from NAP is going to be awfully tiring knowing that you will have a long layover in SIN.