If you're driving into Paris, don't try to go straight across the city to your destination. Use the ring road - the boulevard périphérique - to get to the porte nearest to your destination: it's much quicker, except at rush hour, and easier to find your way at any time. Once ensconced at your accommodation, you'd be well advised to park the car at your hotel and use public transport, as parking is a major problem in the city centre.