There's a great map on the Hotel Beaubourg web site: http://www.beaubourg-paris-hotel.com/English/Location.html

If I recall correctly, our dear friend, Ziner Fabio, stayed at the Hotel Beaubourg when he met us in Paris in 2000. After that 3-week trip, we wrote a huge four-part travelogue. Since we stayed in the Marais, there are probably numerous tips your friend might find useful.

Hope that helps, Linda in Toronto, Canada http://www.thetravelzine.com/paris1100.htm