Tourism in Ottawa

So it looks like I may have to fly 3,000 miles to Ottawa, Canada two weeks from now to run a 20-minute errand. (Yes, I’m serious. Long story. Don’t ask. Just understand that the Libyan tourism-visa bureaucracy is something to behold. And thank goodness airfare to that city is cheap at the moment.)
Anyway, I’ll have two days while I’m in town. I’ve been to Victoria and Vancouver many times, Montreal and Quebec City once each, but never to Ottawa. Does anyone live there or know the city well enough for some recommendations? (Please use the comments.)
I’ll be staying downtown, of course. What I really want to know is…which part of town has the best eye-candy? I like old buildings and walking around the quaint pre-automobile parts of cities – when such places exist, that is. Also, anything with a French theme is good. I know my own Anglo culture pretty well already.
I’ll post pictures.