Maps of Paris

The Ultimate Google Paris Metro Map
Satellite photo of Paris overlaid with Metro Routes. Zoom in to building level, so it's great for checking out the whole city and ideal for tourists! You can work out your route between any two points automatically (it pops up!), and it gives you clear directions - including line changes - and estimated time. Click the Unon Jack for English.

Zoomable Hot-Map of Paris
The german website Hot-Maps has a great zoomable road map of Paris that's very clear and will size to your screen resolution

The RATP website has some maps for printing out, good for residents and tourists:

• Paris Zones Map PDF
• Paris Métro Map PDF
  Paris RER Map PDF
• Paris Bus Map PDF
• Late-Night-Bus Bus Map PDF

And also the City of Paris site:
Bike Paths in Paris Map PDF In French, check P.2

Walking Routes around Paris

And if you're looking for walking routes around Paris, I can't do better than to recommend Geoffrey and Carole Howard's Great Paris Walk Pack : five great walks, five great Paris neighbourhoods:

TRAVEL TO PARIS WITH US: PHOTO HIGHLIGHTS