I'm a big fan of the Streetwise Paris laminated map of central Paris.

It folds to a convenient size, has a street index on the back and really stands up to the wear and tear of opening and closing hundreds of times. It also has a metro map on the back, as well as a list of parks, museums and other places of interest. I buy one, if available, for every city I visit.

I also agree with Frances about the Michelin's Paris Atlas par Arrondissements. You can't beat it for determining if the street you want is a "blvd", "rue", "ave" or "pass". There's also a slightly larger Michelin book (#11) called Paris Plan that I find a bit more convenient (of course, my wife's the one that carries it - in her purse).

Al Sonoma, CA, USA