Is parking still free in Paris the whole August and on Saturday&Sunday, as I can remember it was a year or two ago?

I'll be arriving on car on Friday 7/31 and leaving Sunday 8/2 staying at SPG's Prince de Galles (Av. George 5/Champs d'Elysses). Will it be possible to find a downtown [free] parking place during that time, or would it be better to park outside Paris and take the RER/Métro into the city? I'm coming in from East on A4.