A collegue of mine and I will spend an extra evening in Paris after our meetings are over (5 PM), and are seeking advice on how to pass the time.

Thanks!

Take a walk. Paris is agreat walking ciy. Have dinner, outdoors if warm enough. If there is a bad restaurant in Paris(McDonalds and the like excluded) it would be hard to find.

I second taking a walk. Buy Frommers pocket guide to walking tours of Paris. Walk around the Ile de la Cite and the Ile Ste Louis, both along the river and past Notre Dame.

Take a bateaux mouche ride down the Seine. Paris at night is beautiful, and the architectural details of the bridges can best be seen from the river.