Subject: Driving in France

My trip to northern France is coming together, more or less. Just another practical question: I have been already told by some of you how troublesome can be driving in and out of Paris, but my trips around Ile-de-France will probably take me to the outer ring several times. So my question is: driving from east to west or north to west, is it easier to drive the highways into Paris to the Boulevard Peripherique (ring road), go around and then take the way out, or it's better to take minor side roads keeping well out of town?

Also, is there some strange road law you discovered in France you didn't know before?

Many thanks for assistance and regards

Paolo Trieste, Italy